* “Ebooks” are titles that were released first in electronic form but may have been released in print form later. The graph includes all categories in the Library of Congress Classification of titles that refer to subject matter or disciplines that are within the humanities as the field is conceptualized for the purposes of the Humanities Indicators. See the supplemental table for details.
Source: Developed from a compilation by Stephen Bosch, University of Arizona, of data provided by Ingram Content Group (Coutts Information Services) and YBP Library Services. Prices adjusted for inflation using the gross domestic product deflators produced by the U.S. Department of Commerce’s Bureau of Economic Analysis.