More than one out of three average Americans used a prescription opioid painkiller in 2015, despite growing concerns these medicines are promoting widespread addiction and overdose deaths, a new federal study shows. Nearly 92 million U.S. adults, or about 38 percent of the population, took a legitimately prescribed opioid like OxyContin or Percocet in 2015, according to results from the National Survey on Drug Use and Health. "The proportion of adults who receive these medications in any year seemed startling to me," said study co-author Dr. Wilson Compton, deputy director of the U.S. National Institute on Drug Abuse. "It's an awful lot of people who take these, mostly for medical purposes, but within that a significant percentage end up misusing them," he added. The survey found that 11.5 million people, or nearly 5 percent of the population, misused prescription opioids they'd obtained through illicit means...About 1.9 million Americans (0.8 percent) reported full-fledged opioid addiction.