A new report shows large employers spent $2.6 billion to treat opioid addiction and overdoses in 2016, an eightfold increase since 2004. More than half went to treat employees' children.

The analysis released Thursday by the nonpartisan Kaiser Family Foundation finds such spending cost companies and workers about $26 per enrollee in 2016. "Average inpatient expenses for opioid addiction treatment totaled $16,104 per year in 2016, up from $5,809 in 2004," the report said.

Employers have been limiting health insurance coverage of opioids because of concerns about addiction. The report finds spending on opioid prescriptions falling 27 percent from a peak in 2009.

Get Breaking News Delivered to Your Inbox

Among other findings in the Kaiser report: Older people account for the greatest use of opioids, with "22 percent of people age 55-64 having at least one opioid prescription in 2016."

Researchers analyzed insurance claims from employers with more than 1,000 workers. Most are self-insured, meaning they assume the financial risk.

Workers share the costs. Steve Wojcik of the National Business Group on Health said for every $5 increase, employers typically cover $4 and pass $1 to workers.