More than 18 percent of new textbook revenue in the higher education and career education markets will come from digital textbooks by 2014, according to a new study by Xplana.

By 2014, annual revenues form digital textbooks will surpass $1 billion. The shift in sales will cause the publishing industry to revamp the traditional textbook production processes.

"Everyone wants to know when the digital textbook market for Higher Education will hit the 'tipping point,'" says lead author Rob Reynolds, Director of Product Design and Research for Xplana.

"Our research shows that digital textbooks will begin disrupting the market once their sales surpass 13% of print textbooks sold. Our estimates show digital textbook sales crossing that mark within five years, although it will likely happen even sooner."

Xplana says the cost of textbooks remains the strongest determining factor in the purchase decision for most students. With digital textbooks from many publishers selling for 50 percent of print textbook prices, students will continue to turn to digital.

Overall, the study predicts prices for digital textbooks will remain significantly lower than their print counterparts, which will continue to drive the sales of digital books.