A new study of high school seniors finds 20 percent say they have engaged in binge drinking—having five or more drinks on one occasion—in the last two weeks. Ten percent say they have had 10 or more drinks on one occasion, known as extreme binge drinking, and 5.6 percent had consumed at least 15 drinks.

The findings come from a survey of more than 16,000 students between 2005 and 2011, Reuters reports. Boys were more likely than girls to engage in binge drinking, as well as extreme binge drinking. White students were more likely than black and Hispanic students to be extreme binge drinkers. Students who had 10 or more drinks at a time were more likely to live in the South and in rural areas.

“Students were drinking two or three times the typical binge drinking threshold,” said University of Michigan researcher Megan Patrick. “Consuming 10 or 15 drinks at one time is a lot of alcohol, especially for a teenager. Understanding the negative consequences that go along with these very high rates is important.”

The findings appear in JAMA Pediatrics.

Ralph W. Hingson and Aaron White, from the National Institute on Alcohol Abuse and Alcoholism, noted in an accompanying editorialthat while reported levels of binge drinking have been decreasing among teens, medical emergencies involving teen drinking have not.

“These findings might help explain why some consequences of underage drinking, such as hospitalizations for overdoses, are on the rise, despite general declines in binge drinking,” they wrote.