An astonishing one in 12 doctors have received money directly from drug companies marketing opioids, and that came out to 68,177 doctors receiving $46 million between 2013 and 2015, a new study has found. Researchers are billing this as the first attempt to look into the practie of pharamceutical companies trying to market their drugs directly to the physicians.

It comes as the nation is grappling with an opioid epidemic. More than 52,000 people died due to an overdose of an opioid drug in 2015, and overdoses have jumped greatly in the first nine months of 2016. While some of those deaths can be attributed to powerful drugs like heroin and fentanyl, many are due to people overdosing on normal prescriptions, and many heroin users were introduced to opioids through prescriptions.

Interestingly, doctors were paid the most for promoting fentanyl, an incredibly powerful opioid that is typically used to treat post-surgical pain and for end of life care.

“One in twelve physicians – and nearly one in five family medicine physicians – accepted payments from pharmaceutical companies related to opioids, according to a new study out of Boston Medical Center’s Grayken Center for Addiction Medicine,” reads a statement from the Boston University Medical Center. “This is the first large-scale, national study of industry payments involving opioids and suggests that pharmaceutical companies may have a stronger hold than previously known on how doctors prescribe the powerful drugs. The study results are published online ahead of print in the American Journal of Public Health.”