What are we reading? Reading patterns among users of Madrid’s public libraries

Introduction

Academic studies on reading habits in Spain reflect a growing interest in understanding what, why and how much people read. One of the most important data sources in this area is the Barómetro de hábitos de lectura y compra de libros. According to the most recent edition (Conecta, 2025), 65.5% of Spaniards read books for leisure in their free time and 51.2% are frequent readers, meaning they read daily or weekly. However, there are notable gender differences: 71.7% of women read books for leisure compared to 59% of men. Around 75.3% of young people aged 14 to 24 read in their free time, and reading is also prevalent among children: 78% of parents read books to their children under six, and 82.5% of children between six and nine read in their free time. According to this report, 28.8% of the Spanish population visited a regular library or mobile library in the past year, with the vast majority (91.9%) being public libraries.

The survey Encuesta de hábitos y prácticas culturales en España 2024-2025 (Ministerio de Cultura, 2024) provides similar findings: 60.2% of the population reads for leisure (65.3% of women and 54.9% of men), and 29.2% either visited a library or accessed one online.

Interestingly, in literary creation there is a gender gap in the opposite direction: according to the Estadística de la edición española de libros con ISBN (Ministerio de Cultura, 2025), of the 62,760 books registered with a single author and an ISBN, 60.3% were written by men and 39.7% by women.

In November 2024, the polling company 40dB conducted a survey titled Radiografía de la lectura en el siglo XXI for the newspaper El País and the broadcasting network Cadena Ser, based on interviews with 2,000 people (40dB, 2024). The results were consistent with those cited above: 55% of the population reads regularly (daily or weekly) and women are more likely to be regular readers (60% vs. 50% of men). The survey also asked respondents to name authors they considered especially important and books that had changed their lives, that they had recently given as gifts, or that they kept on their nightstands. The results revealed the eclectic nature of readers’ preferences: 72% of participants mentioned a significant book in their lives that was not cited by anyone else, although bestsellers were strongly represented. While there was no consensus on the most important author of the 21st century, Arturo Pérez-Reverte was mentioned by 20% of respondents. In relation to book format, 46.6% of respondents said they borrowed printed books from libraries, and 26.5% borrowed electronic books.

In recent years, social media has become another source of insight into readers’ preferences. Numerous studies in different countries have explored user reviews on Goodreads, a social platform dedicated to books and reading owned by Amazon. In Spain, Sánchez-García et al. (2021) analyse Goodreads reviews to study the reception of 19 Spanish children’s and young adult books between 2016 and 2019. In Mexico, Reyes-Abundes and Cebral-Loureda (2024) examine readers’ experiences of Fernanda Melchor’s work through user reviews on the platform.

Lluch (2023; 2025) has collected data to develop a non-academic literary canon, considering prize-winning fiction for children and young adults (Gómez-Díaz & García-Rodríguez, 2024) and for adults (Gómez-Díaz & García-Rodríguez, 2024), as well as books reviewed in the press, recommended by book influencers, or frequently borrowed from libraries and selected for reading clubs (Baldaquí-Escandell & Lluch, 2024), among others.

The methodologies of most of the studies on reading habits discussed above involve surveys, a method that has the limitation of depending on voluntary participation. On the other hand, bestseller lists published occasionally by the press or specialised magazines typically include only a small number of titles and, due to the commercial sensitivity of the data, rarely report exact sales figures.

In this context, library book lending data remains an underexplored source for the analysis of reading habits, probably because such data is not usually made publicly available. However, these records can provide evidence of what users actually read, offering a complementary perspective for the analysis of reading behaviour. Although the data cited above indicates that the use of public libraries is limited to around 30–40% of the population, this is a significant enough segment to merit attention —especially considering it probably includes a substantial group of habitual readers. Moreover, while library collections may place some constraints on user choices, they are generally broad and curated by professional librarians who work hard to maintain a balance between the publishing market and readers’ interests.

This study explores the potential of public library loan data as a source of information on the reading preferences of both adult and child users, based on the loan records of the municipal library network of Madrid, available via the Madrid City Council’s Open Data Portal (Ayuntamiento de Madrid, 2025). Madrid has been chosen as a case study primarily due to the availability of data. The research conducted for this study has not identified any other public library network in Spain that publishes loan information in such detail. Moreover, the volume of data provided by the Madrid public library network is sufficiently large to ensure the robustness and representativeness of the analysis.

The objectives of this study are:

Methodology

Results

Loans to adult users

In 2024, adult users of the Madrid public library network made a total of 1,770,833 loans of 164,731 different titles published by 63,931 authors. Table 2 presents the 15 authors whose works registered more than 4,000 loans in the year, indicating the number of different titles (not copies) borrowed and the total number of loans. Table 3 lists the 15 most borrowed titles. The full lists of authors and titles can be obtained using the code described in the Methodology section.

Table 2Authors with works most borrowed by adult users in Madrid public libraries in 2024 

Author	Titles	Loans
Gómez-Jurado, Juan (1977-)	34	7,201
Santiago, Roberto (1968-)	80	6,926
Pérez-Reverte, Arturo (1951-)	79	6,232
Stilton, Geronimo	346	5,976
Mañas Romero, Pedro (1981-)	83	5,938
Pilkey, Dav (1966-)	73	5,425
Mola, Carmen	8	5,378
Maxwell, Megan (1965-)	59	5,286
Ibáñez, F. (1936-2023)	366	4,984
Silva, Lorenzo (1966-)	67	4.979
Kinney, Jeff (1971-)	60	4,933
Läckberg, Camilla (1974-)	34	4,690
King, Stephen (1947-)	144	4,600
Zweig, Stefan (1881-1942)	105	4,426
Allende, Isabel (1942-)	36	4,194

The results reveal a strong preference for the thriller genre, as one third of the most borrowed authors specialize in series in this category. There is also a notable presence of authors whose work is primarily aimed at children, despite being among the most borrowed by adult users. Japanese manga also clearly stands out among the most borrowed titles.

Table 3Books most borrowed by adult users in Madrid public libraries in 2024 

Title	Author	Loans
My Hero Academia	Horikoshi, Kohei (1986-)	1,796
Naruto	Kishimoto, Masashi (1974-)	1,787
Tokyo Revengers	Wakui, Ken	987
El infierno	Mola, Carmen	973
La Bestia	Mola, Carmen	966
Berserk	Miura, Kentaro (1966-2021)	939
Todo vuelve	Gómez-Jurado, Juan (1977-)	920
Reina roja	Gómez-Jurado, Juan (1977-)	900
La novia gitana	Mola, Carmen	896
El cuco de cristal	Castillo, Javier (1987-)	887
Super patata	Laperla (1975-)	873
La Nena	Mola, Carmen	870
El problema final	Pérez-Reverte, Arturo (1951-)	868
Un amor	Mesa, Sara (1976-)	852
Nada	Laforet, Carmen (1921-2004)	839

A select number of authors and titles dominate the loan data. Specifically, 11.7% of the most borrowed authors account for 80% of the total loans made to adult users, while 24.2% of the most borrowed titles represent 80% of the total borrowed. This pattern suggests a high concentration of reader interest in a relatively small group of authors and books.

Figure 1 visualizes this concentration of loans with two Lorenz curves: one for authors and one for titles. The dashed diagonal line represents what a perfectly equitable distribution would look like, where each author or title contributes proportionally to the total number of loans. The further the curve deviates from this diagonal, the greater the concentration of loans among a limited number of authors or books. The Gini index, derived from the area between the Lorenz curve and the line of equality, quantifies this inequality on a scale from 0 (perfect equality) to 1 (maximum inequality). In this case, the Gini index is 0.84 for authors and 0.72 for titles, indicating a strong concentration of loans among a small number of authors and, to a lesser extent, titles.

Figure 1Cumulative distribution of loans by authors and titles in Madrid public libraries in 2024 

There is a clear relationship between the number of works available by an author and that author’s total number of loans: authors with longer careers and a larger number of books in the library catalogue tend to register more loans. The points on the chart in Figure 2 represent different authors, whose positions are determined by the number of titles they have in the library catalogue and the total number of loans for their works. The trend line shows the best-fitting linear regression that describes the relationship between the two variables.

This regression suggests that a higher number of titles is generally associated with a greater number of loans. The Pearson correlation coefficient is 0.65, indicating a moderately strong linear relationship between the two variables. The regression model has an R² of 0.43, meaning that approximately 43% of the variability in the number of loans can be explained by the number of titles available by the author. The model is statistically significant (p < 0.001). However, the standard deviation of the residuals is 112.7, meaning that the model’s prediction for an author’s number of loans differs on average by ±112.7 loans from the actual value. This suggests that there is still considerable unexplained variability in the model, probably due to other factors such as the author’s popularity, the subject matter of their works, or their presence on conventional and social media.

Figure 2Relationship between number of titles and loans per author 

Tables 4 and 5 present a breakdown of the number of loans by gender and nationality of the 515 authors whose works are borrowed the most by adult users in Madrid’s public libraries. The findings for gender (Table 4) reveal that nearly two thirds of the most borrowed authors are men (61%), who account for a very similar percentage of the loans (62%), while women represent 39% of the authors and 38% of the loans. This male overrepresentation reflects the gender gap observed in literary creation (Ministerio de Cultura, 2025).

Table 4Gender of the 515 authors with works most borrowed by adult users in Madrid public libraries in 2024 

Gender	Authors	% authors	Loans	% loans
Male	316	61%	383,579	62%
Female	199	39%	236,382	38%

The data on nationality (Table 5) shows that works by Spanish authors account for 44% of the loans, probably due both to a strong presence of national literature in Madrid’s public libraries and to a preference for Spanish authors among users. In second place are works by English-speaking authors (American and British), which together represent 29% of loans. Representing a much smaller proportion of the total are French authors (6%) and Japanese authors (3%), the latter mainly due to loans of manga titles. The remaining 18% of loans are of works by authors from 31 other countries.

Table 5Nationality of the 515 authors with works most borrowed by adult users in Madrid public libraries in 2024 

Country	Authors	% authors	Loans	% loans
Spain	203	39%	271,568	44%
United States	92	18%	104,662	17%
United Kingdom	63	12%	73,755	12%
France	36	7%	35,664	6%
Japan	20	4%	21,035	3%
31 countries	101	20%	113,277	18%

For the temporal analysis, the authors’ year of birth was used. This information was available on 25,690 authors who account for 1,266,355 loans, representing 40% of the authors in the dataset and 72% of the total loans.

Figure 3Loans to adult users in Madrid public libraries in 2024 by authors’ decade of birth 

Figure 3 shows that the most popular authors are those born in the 1960s and 1970s, who together account for 40% of the loans. In fact, seven of the 15 authors identified in Table 2 as the ones whose works were borrowed the most were born in these two decades. Among authors born before the 20th century, besides Stefan Zweig, who appears in 14^th place in Table 2, two authors stand out for registering more than 3,000 loans each in 2024: Benito Pérez Galdós (1843–1920) and Agatha Christie (1890–1976). No other authors born before the 1920s exceed this threshold, while three authors born in the 1920s do so: Andrea Camilleri (1925–2019), René Goscinny (1926–1977) and Gabriel García Márquez (1927–2014).

The genre analysis of the 186 books that exceeded 350 loans in 2024 again reveals a clear preference for thrillers among adult users of the Madrid municipal library network (Figure 4). This category, which covers novels classified in the catalogue as “crime”, “suspense”, “noir” or “detective”, includes 77 of the 186 most borrowed titles. All together, these titles account for 42% of the loans. In second place are social novels (24% of titles and 23% of loans), manga (8% of titles and 11% of loans), and historical novels (8% of titles and 7% of loans). Only nine of the 186 most borrowed titles were non-fiction, among which El infinito en un junco by Irene Vallejo stands out for its number of loans.

Figure 4Genre of the 186 titles most borrowed by adult users in Madrid public libraries in 2024 

Discussion

The analysis of book loans during 2024 in the Madrid public library network reveals a strong concentration of reading consumption around a small group of bestsellers. The high Gini indices for both adult loans (0.84 for authors and 0.72 for titles) and children’s loans (0.88 and 0.76, respectively) reflect that a very small proportion of the library catalogue accounts for most of the loans, raising questions about the effective diversity of the content chosen by readers.

Among adult readers, there is a clear preference for thrillers (including crime, noir, detective and suspense novels), which represent 42% of all loans. Authors such as Juan Gómez-Jurado and Carmen Mola dominate the rankings, while Japanese manga stands out among the most borrowed titles. This preference for popular genres among both adult and child users may be related to their more accessible narratives and more aggressive marketing strategies by their publishers. Many of the most borrowed works form part of series of books with similar themes, plots, narrative structure, character development and discursive style (Lluch, 2025, p. 195). The results of this study also seem to confirm the theory that the two age groups (adult and child readers) are converging (Lluch, 2025, p. 191). It is noteworthy that among the most borrowed authors for adults are writers whose work is usually aimed at children, such as Geronimo Stilton, Dav Pilkey or Pedro Mañas, although this may be partly due to the shared use of family library cards.

The data reveal an overrepresentation of males among authors with the most borrowed titles (61%), consistent with findings related to the persistent gender gap in literary creation. According to data from the Spanish Ministry of Culture (Ministerio de Cultura, 2025), 60.3% of books with an ISBN registered under a single author were written by men. Similarly, the nationality of authors reveals a strong presence of Spanish literature (44% of loans) and works by English-speaking authors (29%), probably reflecting both the structure of the collections and readers’ preferences.

Authors born in the 1960s and 1970s are responsible for a significant proportion of the titles borrowed, which may be because authors of this age are actively publishing and have a strong media presence. However, there is also considerable demand for classic authors such as Stefan Zweig, Benito Pérez Galdós and Agatha Christie, who continue to be regularly read many decades after their publication.

In loans to children, the concentration pattern is even more pronounced than it is among adults, with 80% of loans attributable to just 7.8% of authors and 18.9% of titles. Established figures such as Roberto Santiago, Jeff Kinney and Dav Pilkey dominate the statistics, and there is also a notable presence of Japanese manga. Sagas, graphic humour, and recurring characters appear to play a key role in fostering loyalty among child readers.

Another significant finding is the limited overlap between the authors with most borrowed works identified in this study and those who usually receive attention from other agents in the literature ecosystem, such as literary prize juries. Gómez-Díaz and García-Rodríguez (2025) identified 16 Spanish authors with the most literary awards between 2000 and 2020. Of these, only half are among the 500 authors who registered the most loans in Madrid’s public libraries in 2024: Lorenzo Silva (in 10^th place), Almudena Grandes (21^st), Fernando Aramburu (53^rd), Javier Cercas (79^th), Javier Marías (123^rd), Ignacio Martínez Pisón (150^th), Rafael Chirbes (156^th) and Álvaro Pombo (226^th). This group is comprised largely of authors with a strong media presence. In contrast, other authors with multiple awards but less media visibility rank much lower in the research results: Antonio Soler (749^th), Cristina Fernández Cubas (990^th), Javier Negrete (1,122^nd), Francisco López Serrano (10,717^th), José Antonio Ramírez Lozano (15,466^th), Marcelo Luján (21,389^th), Miguel Sánchez Robles (23,987^th) and Blanca Riestra (33,062^nd).

The 2023 edition of the Barómetro de hábitos de lectura y compra de libros (Conecta, 2024) included a ranking of the ten most read authors according to survey responses. Only one of these authors appears among the top ten most borrowed in Madrid’s public libraries: Arturo Pérez-Reverte, who was also cited as a key author in the 40dB Radiografía de la lectura en el siglo XXI (2024). Five other authors mentioned in the Barómetro rank within the top 100 authors who registered the most loans in Madrid libraries in 2024: Ken Follett (35^th), Julia Navarro (45^th), Gabriel García Márquez (52^nd), J. K. Rowling (55^th) and Carlos Ruiz Zafón (75^th). The remaining four authors are further down in the loan statistics: J. R. R. Tolkien (173^rd), Ildefonso Falcones (225^th), Antoine de Saint-Exupéry (394^th) and Dan Brown (446^th).

It is worth noting some of the limitations of this study. First, it focuses exclusively on physical book loans, as digital loans, managed via platforms such as eBiblio, are not included in the analysed dataset, which means the study excludes a significant portion of reading consumption. Second, the database lacks detailed sociodemographic information about users (age, gender, education level, etc.), preventing direct correlation between reader profiles and borrowing patterns. Only a broad distinction between adult and child users is possible, which hinders the interpretation of the data from the perspective of sociology or audience studies.

Conclusion

This analysis of loans in Madrid’s public library network during 2024 reveals a marked concentration of authors and titles in the borrowing patterns of both adults and children. The findings confirm the prominence of popular genres such as thriller and manga, as well as reader loyalty to certain sagas and authors.

The predominance of authors born in the 1960s and 1970s, along with the dominant presence of Spanish, American and British literature, underscores the role of libraries as mirrors of contemporary cultural dynamics. Other findings include the continued reading of classics and a significant circulation of translated literature. Moreover, the study identifies persistent inequalities, such as the overrepresentation of males among authors who register the most loans, which is consistent with publication data.

Despite its limitations (such as the exclusion of digital loans and lack of detailed sociodemographic data on users), this analysis confirms the great value of loan data as a complementary source for the analysis of reading habits, enabling observation of real cultural consumption practices in a public, free and accessible environment. This study aims to encourage other libraries or networks to begin publishing this type of information. In a context of increasing calls for administrative transparency, there are good reasons for making these data publicly available, and the experience of the Madrid public library network demonstrates that it can be done without compromising user confidentiality.

While the field of reading studies tends to rely on surveys and published market data, library loan systems offer a valuable alternative perspective, providing empirical information about what is being read in shared reading spaces. Improving access to this information for its analysis and dissemination could significantly enrich our understanding of reader habits and reading promotion policies.