A growing number of young people being booked into jail in Hennepin County, Minnesota, which includes Minneapolis, are using painkillers, according to KARE11. The findings are part of a nationwide report conducted by the Associates for the Office of National Drug Control Policy.

“It’s astounding to me how many people we see come in here who’ve used prescription drugs,” Marty Hamlin, the nurse manager at the jail, told the news station.

The study includes 10 sites nationwide: Atlanta, Charlotte, Chicago, Denver, Indianapolis, Minneapolis, New York, Portland, Sacramento and Washington, DC.

The study found the proportion of arrestees nationwide who tested positive for some substance in their system at the time of arrest was high across all sites—more than 60 percent in nine of the 10 sites and as high as 80 percent or more in two sites, Chicago and Sacramento.

The most commonly detected drug in 2010 was marijuana. Positive tests ranged from 35 percent in Atlanta, to 58 percent in Sacramento. Cocaine was the next most commonly detected drug in eight of the 10 sites, ranging from 17 percent in Washington, DC, to 33 percent in Atlanta.