It’s been called the worst drug crisis in American history—a surge in opioid use that is crowding emergency rooms, taxing local officials and putting lives at risk. But what are the latest statistics on just how many people use opioids? One new study offers answers for one opiate: heroin. As Nicola Davis reports for The Guardian, the latest study shows that in the United States heroin use increased nearly fivefold during the last decade.

The study, which was published in the journal JAMA Psychiatry, relied on data from the National Epidemiologic Survey on Alcohol and Related Conditions. In 2001 and 2002, researchers conducted large-scale studies of American adults, interviewing roughly 40,000 people face-to-face about their drug and alcohol use. A similar study took place in 2012 and 2013. When the team compared data from the first time period with the second, they found a dramatic increase in both use of heroin and what’s known as heroin use disorder, a condition in which people experience significant impairment or distress from their heroin use, including the inability to quit or developing a tolerance.

Heroin use rose from 0.33 percent in 2001-2002 to 1.61 percent in 2012-2013, with heroin use disorder rising from 0.21 percent to 0.69 percent during the same time period. When asked if they had used heroin in the past year during 2012 and 2013, 0.21 percent said yes, up from 0.03 percent in 2001-2002.

The data showed gaps in both race and the use of other drugs. During the first study period, white and non-white people reported roughly the same amount of heroin use. But that number changed in 2012-2013. While 1.05 percent of non-white people reported heroin use, that number was 1.9 percent for white people. And people who had used prescription opioids for recreational purposes were more likely to report using heroin, too: 36 percent of white recreational prescription opioid users said they’d used heroin in 2001-2002, while 53 percent gave the same answer during 2012-2013. Urban respondents were more likely to report heroin use, as were males, unmarried people, and people with a high school education.

The study did have limitations. Though the sample size was fairly large, it still represented a fairly small percentage of the over 3 million people living in the states. The data also depends on information individuals gave to survey takers, so people could have underreported or misreported their drug use. But it confirms what ER workers and addiction specialists could have already told you: Heroin use has risen.

Silvia Martins, who led the study, tells Davis that there’s a need for better treatment, prescription drug monitoring, and more training for medical professionals. In a press release, she says she expects the number of people with heroin use disorder to rise as the drug becomes more popular.

There are ways to treat heroin addiction. Suboxone, methadone and other drugs can help people recover, Naloxone can treat overdoses, and needle exchanges can keep people who do inject heroin safe from viral infections like hepatitis B and C and HIV. But opioid treatment continues to be controversial—even as the epidemic of people who use opioids grows. But this latest study adds to the evidence that opioid use is on the rise, perhaps helping to spur action among public officials.