* “Print books” are titles that first appeared in print form but may have been released in an electronic format later. Print titles include hardcover and paperback books. Please see the supplemental table for information about which disciplines were included in the broad field categories used in the graph.
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.