Life expectancy in the U.S. has fallen for the second year in a row, the first time it’s dropped for two consecutive years in more than half a century.

People born in the U.S. in 2016 could expect to live 78.6 years on average, down from 78.7 the year before, according to a new report released Thursday by the Centers for Disease Control and Prevention. The most common cause of death: heart disease.

The report also found death rates — calculated from the number of deaths per 100,000 people — actually rose among young adults between 2015 and 2016. And while the authors didn’t draw a direct link, another report also released Thursday by the CDC found an estimated 63,600 people died of drug overdoses in 2016. Two-thirds of those deaths were caused by opioids. Adults between the ages of 25 and 54 had the highest rate of drug overdose death.

Here’s a look at the findings:

Most common causes of death

Heart disease was the leading cause of death, followed by cancer, unintentional injuries, chronic lower respiratory diseases, stroke, Alzheimer’s disease, diabetes, influenza and pneumonia, kidney disease, and suicide.

One key point: Unintentional injuries climbed to the third leading cause of death in 2016, swapping spots with chronic lower respiratory diseases. It’s worth noting that most drug overdose deaths are classified as unintentional injuries.

Black men are dying at alarmingly high rates

Life expectancy isn’t falling for women — just for men. Life expectancy for women at birth is 81.1 years, compared to 76.1 years for men.

The death rate for the general population actually declined slightly in 2016, but that drop wasn’t seen across all racial and ethnic groups. Death rates among black men climbed 1 percent in 2016, while death rates among white women actually fell 1 percent. There weren’t any big changes in death rates among black women, white men, or Hispanic men or women.

Drug overdose deaths continue to climb

Drug death rates are increasing much faster than they have in recent years. Overdose death rates climbed roughly 10 percent per year between 1999 and 2006. Then there was a relative lull: Between 2006 and 2014, they increased roughly 3 percent each year.

But from 2014 to 2016, death rates tied to drug overdoses jumped 18 percent each year.

Deaths due to synthetic opioids are rising

The rate of overdose deaths involving synthetic opioids other than methadone — a category that includes fentanyl, fentanyl analogs, and tramadol — doubled between 2015 and 2016. The rate of drug overdose deaths involving natural and semisynthetic opioids, such as oxycodone and hydrocodone, also rose, while overdoses involving methadone declined.