The high cost of college textbooks is not only hurting students' wallets; it's hurting their grades.

A U.S. Public Interest Research Group (PIRG) survey found that the average student spends as much as $1,200 each year on textbooks, reports U.S. News. What's more, 65 percent of students simply decided not to buy a required book for class, even though 94 percent were concerned it would hurt their grade.

U.S. News reports the costs of textbooks have increased by 82 percent in the last decade because there isn't a strict control over book prices.

A higher education associate at U.S. PIRG, Ethan Starke, told reporters, "Students are paying too much for textbooks, plain and simple."