One year after its publication To Kill a Mockingbird had been translated into ten languages. In the years since, it has sold more than 30 million copies and been translated into more than 40 languages. The novel has never been out of print in hardcover or paperback, and has become part of the standard literature curriculum. A 2008 survey of secondary books read by students between grades 9–12 in the U.S. indicates the novel is the most widely read book in these grades. A 1991 survey by the Book of the Month Club and the Library of Congress Center for the Book found that To Kill a Mockingbird was rated behind only the Bible in books that are "most often cited as making a difference".[note 1] It is considered by some to be the Great American Novel.