For the second year in a row, college students spent less on textbooks and other course materials. The findings, from two new reports, link the spending drop to a rise in the use of rented materials and digital textbooks. The reports cite that digital materials can cost 15-70% less than new print textbooks.

The Student Watch Survey, conducted by the National Association of College Stores, reported a decline of $23 per student in spending; it dropped from $602 during the 2015-2016 academic year to $579 during 2016-2017. Student Monitor, an independent study of student spending issued twice a year, reported a decline of $64 in spending per student, dropping from $607 during the 2015-2016 year to $543 in the 2016-2017 academic year.

More students than ever—82% of the respondents in the Student Monitor survey—are using comparison shopping. Students, the reports said, are taking advantage of the competitive market for course material, where there is an increased variety of low-priced options.

The Student Watch survey reported that as many as 52% of students use digital course materials. According to this study, renting a textbook costs about $30 less than buying one. More than 33% of the respondents in the Student Watch survey said they had rented one or more textbooks; that figure marks a record high.

The combination of digital material and a more competitive market is bringing down prices overall. The average price of a new print textbook, according to the Student Monitor survey, declined by 13%; it dropped from from $91 to in 2015-2016 to about $80 in 2016-2017.

The Student Monitor survey collects data from 1,020 full time four-year colleges in the U.S. The Student Watch survey collects responses from more than 44,000 students from 90 two- and four-year colleges in the U.S. and Canada.

David Anderson, executive director of higher education at the Association of American Publishers, said the studies show that students are taking advantage of technical innovation. “Over the past few years learning companies have championed multiple solutions, which are effectively reducing the cost of course materials, including the shift to digital.”