A new government report shows prescription drug abuse decreased in 10 states from 2010 to 2011, and did not increase in any state.

The report by the Substance Abuse and Mental Health Services Administration (SAMHSA) found 22 million people began the nonmedical use of pain-relieving drugs since 2002. Prescription drug abuse is just behind marijuana as the country’s most widespread drug issue, the report concludes.

Iowa had the lowest rate of prescription drug abuse, at 3.6 percent, while Oregon had the highest rate, at 6.4 percent. Seven of the 10 states with the highest levels of prescription painkiller abuse were in the West—Washington, Oregon, Nevada, New Mexico, Idaho, Colorado, and Arizona, according to Medical News Today.

“Addressing prescription drug misuse remains a top public health priority, as we’ve seen inconsistent progress in addressing the issue across the states,” SAMHSA Administrator Pamela S. Hyde said in a news release. “Data from this report helps us better understand geographic variations in use, and should help with the development of more targeted and effective prevention and treatment programs. The key is educating the public on the serious health risks involved, and ensuring that we are providing the necessary treatment to those who need it.”