Opioid prescriptions dropped in most Oregon counties between 2010 and 2015, according to new federal data.

But there were four outliers: Malheur, Morrow, Union and Wallowa counties, where providers handed out more opioids per capita in 2015 compared with five years prior, according to data obtained by The Oregonian/OregoLive from the U.S. Centers for Disease Control and Prevention.

A CDC report, released Thursday, included a graphic showing prescriptions on a county-by-county basis across the country. To level the playing field among various drugs and doses, it used what's known as the morphine milligram equivalent, which measures potency.

In Oregon, Curry County prescribers gave out the most opioids per person in 2015, followed by Baker and Malheur counties. At the bottom of the list -- Grant County.

Populous Multnomah County ranked No. 30 among the 35 counties with 2015 data. Sherman County did not report for either year.

State health officials have been pushing providers to limit the use of opioids to treat chronic pain amid an opioid epidemic that's swept the country.

Nationwide, prescriptions also dropped, offering a glimmer of progress in efforts to quell the drug crisis.

The CDC said prescriptions for highly addictive painkillers such as oxycodone fell 13 percent between 2012 and 2015, from 81 prescriptions per 100 people to 71.

Anne Schuchat, the CDC's acting director, expressed tempered optimism about the first national decline in opioid prescriptions that the CDC has reported since the crisis began in the late 1990s.

She said the prescription rate is still triple the level it was in 1999 and four times as much as it is in some European countries. Even at the reduced prescribing rate, she said, enough opioids were ordered in 2015 to keep every American medicated round-the-clock for three weeks.

"It looks a little bit better, but you really have to put that in context," Schuchat told the Washington Post. "We're still seeing too many people get too much for too long."

The U.S. counties with the highest doses in 2015 – Martinsville City, Virginia, followed by Norton City, Virginia -- gave out six times more opioids than the lowest-prescribing counties, Clark, South Dakota, with Long, Georgia, on the bottom, the CDC said.

Taking opioids for longer periods of time or in higher doses increases the risk of addiction, overdose and death.

The Washington Post contributed to this story.

-- Lynne Terry