And a separate study conducted by the Government Accountability Office found that textbook prices nearly tripled from 1986 to 2004 -- a jump that's twice the rate of annual inflation over the last two decades.
Public-interest groups say this is a rip-off. They blame greedy publishers and bookstores for driving up prices by issuing unnecessary new editions that render older texts worthless without adding much new information, as well as by "bundling" books with other materials like CD-ROMs.
Students have no choice but to buy the textbooks for their courses. But don't worry, kids -- at the end of the semester, you can probably sell that $250 calculus tome back to the bookstore for a buck or two.
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