Death rates in the United States have declined for the first time since 2014, in part due to the drop in fatal drug overdoses, NPR reports.

Life expectancy increased slightly, according to the Centers for Disease Control and Prevention (CDC). In 2018, life expectancy at birth was 78.7 years, 0.1 years longer than the previous year, the CDC said in a new report.

The average lifespan in the United States reached 78.9 years in 2014, then declined, largely due to drug overdose and suicide deaths.

In 2018, there were 4.1% fewer drug overdose deaths than the previous year. Most of the decline was seen in deaths involving natural and semi-synthetic opioids. That “includes drugs like oxycodone, which are commonly available by prescription,” said Bob Anderson, Chief of the Mortality Statistics Branch at the CDC’s National Center for Health Statistics, who oversaw the new reports. “We [also] saw declines in deaths involving methadone and even … heroin.”