Nearly 6 percent of college students reported using pot daily or near-daily in 2014, up from 3.5 percent in 2007 but less than the 7.2 percent recorded in 1980, the University of Michigan’s Monitoring the Future study found.

Less frequent pot smoking was also on the rise, according to the study, although not as sharply.

“It’s clear that for the past seven or eight years there has been an increase in marijuana use among the nation’s college students,” said Lloyd Johnston, the study’s principal author. “And this largely parallels an increase we have been seeing among high school seniors.”

Loosened marijuana policies in states across the country have likely contributed to a rise in use by teens and young adults, who increasingly perceive the drug as harmless, the study said.