(CNN) Opioids continue to be prescribed at high rates, a new report from the US Centers for Disease Control and Prevention finds, even as drug overdoses remain the leading cause of accidental death in the country, killing more people than guns or car accidents.

"The bottom line is, we still have too many people getting too many opioid prescriptions for too many days at too high a dosage," said acting CDC Director Dr. Anne Schuchat.

Prescriptions are measured by morphine milligram equivalents, which uses morphine as a baseline to measure the equivalent prescribed opioid, which may be more powerful.

Opioids -- both legal, such as prescription oxycodone and hydrocodone, and illicit drugs, such as street fentanyl and heroin -- killed more than 33,000 Americans in 2015. Half of those deaths involved prescription narcotics.

"Reducing prescriptions is just one part of a bigger charge to address the overall problem. It's a very important piece of the puzzle," Schuchat said.

Prescription opioid-related overdose deaths and treatment of opioid use disorder have trended similarly to the increase in opioid prescriptions, which quadrupled from 1999 to 2010. Much of this increase has been attributed to the increase in opioids being used to treat chronic pain.

"Try to prevent people initiating opioids unless necessary," said Caleb Banta-Green, an associate professor of health services at the University of Washington who was not involved with the new CDC report. "Physical and emotional stress and discomfort are common. We all experience them. Rarely are opioids the best treatment for short-term health conditions."

If the pain is going to last only a week or two, he said, try over-the-counter pain relievers.

Every community is affected

The report, which is the first to offer a county-by-county breakdown of prescribing across the nation, found varied prescribing practices.

The report analyzed retail prescription data at the county level from 2006 to 2015. It found that the top prescribing counties had nearly six times the number of prescriptions as those with the lowest rates of prescriptions.

"Opioid prescribing varies as much from place to place as the weather, and even neighboring counties have major differences in prescribing levels," Schuchat said.

Residents of those counties with the highest prescription rates have a greater risk of opioid addiction, overdose and death as a result of the higher prescribing practices.

The counties with the highest levels of prescriptions tended to have larger white populations, higher rates of unemployment and greater numbers enrolled in Medicaid.

Previous reports have shown that rural areas have been particularly hard-hit, but that is not captured in this report. Schuchat explained that it's because the data are based on where the prescriptions were picked up, not where people with the prescriptions live. Rural areas don't have as many pharmacies, so many residents must travel to have their prescriptions filled.

But there are some places that seem to be succeeding. In Florida, where there have been major efforts to crack down on excessive opioid prescribing between 2010 and 2012, 80% of counties reported a decrease in prescriptions. Likewise, in Ohio and Kentucky, where providers are required to review a database of prescription information by way of monitoring, 85% and 62% of counties reported decreases in prescription practices.

The authors of the study also found that the average dose of prescriptions and the overall rate of prescriptions -- from 81.2 to 70.6 prescriptions for every 100 persons from 2010 to 2015 -- were trending downward.

However, the average length of days for prescriptions increased. The average days' supply prescribed increased 33%, from 13.3 days in 2006 to 17.7 in 2015. A previous study from the CDC found that prescriptions for eight or more days increased the likelihood of using a drug a year later to 13.5%. And although just less than 7% of all prescriptions exceed a month's dosage, using for 31 days or more increased the chances of long-term opioid use to 29.9%.

In an attempt to rein in the over-prescribing of these medications, the CDC established new guidelines for prescribing practices in 2016 emphasizing that non-opioid treatments should be considered first-line therapies for dealing with chronic pain in adults and should be used for chronic pain only when the benefits outweigh the risks. Because the new study looked at prescription data between 2006 and 2015, the study didn't account for the impact of these new recommendations.

However, in 2009, the American Pain Society and the American Academy of Pain Medicine released guidelines aimed at reducing prescribing habits by care providers. The US Department of Veterans Affairs and the US Department of Defense issued a similar set of guidelines in 2010 that focused on reducing prescribed dosages. Schuchat believes these sets of guidelines triggered some improvement, which is reflected in the new report.

Separately, some states -- Connecticut, Massachusetts, Rhode Island, New York and Maine -- have adopted legislation that limits opioid prescriptions to seven days. This year, New Jersey became the strictest, limiting painkiller prescriptions to just five days.

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The study also did not identify whether reducing the number of prescriptions translates directly to an overall reduction in the number of people abusing opioid drugs. The latest numbers from the CDC find that the number of overdoses due to heroin and illicit synthetics are on the rise. In fact, between 2014 and 2015, the percent of overdoses attributed to synthetic opioids, much of it attributed to illicit fentanyl, rose by 72% in one year.

"We know the country is experiencing the highest overdose rates ever recorded, and it's driven by prescription and illicit opioid use," Schuchat said. "Improvements in prescribing (habits) are just the beginning, but we have so much work to do."