The price of college textbooks may be forcing students to suffer academically, according to a report from U.S. Public Interest Research Group.

A survey of student consumers found that 65 percent opted out of buying a college textbook last fall due to price.

"Ninety-four percent of them said that they were concerned it would hurt their grade," said Gayle Schwartzberg, a campus organizer with PIRG's New Jersey chapter.

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Textbook prices have increased by 82 percent over the past decade, according to the advocacy group, which cited a finding from The College Board that says students are spending an average of $1,200 this year on books and supplies.

"Recently, alternatives to brand-new, print edition textbooks have become widely available through rental programs, used book markets, and e-textbooks," the report stated. "While these markets offer students upfront savings, their prices are still dictated by the prices of the new print editions."

Schwartzberg noted publishers continuously work toward creating new editions of textbooks, and the books are commonly sold as a "bundle" with a CD or workbook so the mandatory cost can be even higher.

The group is demanding more "open textbooks" on college campuses. The literature is written by faculty and peer-reviewed, and available for free online with the option to buy a hard copy. The University of Minnesota recently launched an open textbook library.

"If we're going to actually ease the burden of high textbook prices, we need to give students a better, low-cost alternative outside of the traditional market," added Ethan Senack, higher education associate for the U.S. PIRG Education Fund.

Critiques of the PIRG report have called it "amazingly opaque" and one that "plays fast and loose with fact."