The CDC released the official 2017 mortality and drug overdose data this week, and any way you slice it, it’s bad. The numbers show the United States in the midst of the longest sustained decline in life expectancy since World War I. The drop is driven in large part by the drug overdose epidemic, which claimed 70,237 lives, an increase of nearly 7,000 over the previous year.

Joshua M. Sharfstein, vice dean for public health practice and community engagement at the Johns Hopkins Bloomberg School of Public Health, summed it up in an interview with The Washington Post: “I think this is a very dismal picture of health in the United States.”

Separately, however, public health researchers are pointing toward evidence of light at the end of the overdose tunnel. The CDC’s provisional monthly estimates of overdose deaths show more detail and are more recent than the year-end figures. Those numbers show that nationwide, drug overdose deaths peaked in September 2017 and have been steadily declining in the months since.

The data go through April of this year. They show that nationwide, the estimated number of overdose deaths for the 12-month period ending April 2018 was 70,859, a decline of more than 2,000 deaths vs. the 12-month period ending in September 2017.

These figures are provisional and subject to change as states finalize their death certificate data. However, they’ve proved to be fairly accurate in the past. The provisional data for the year ending in December 2017 showed 72,287 overdose deaths, off by less than 3 percent vs. the final number released Friday.

Experts have begun to take notice of this decline and have been weighing in on it with cautious optimism. “Three months ago I wasn’t sure the provisional deaths curve was really going down,” Daniel Ciccarone of the University of California at San Francisco told STAT News in October. “But the trend seems robust.”

Drilling down, the numbers show declining mortality from heroin and opioid prescription painkillers, in particular. The synthetic opioid category, which includes fentanyl, continues to be a chief area of concern, although there’s evidence the rate of increase in fentanyl mortality slowed in 2017 and 2018. Deaths from cocaine, which is not an opioid, have plateaued, while deaths from methamphetamine and other non-opioid stimulants are continuing a modest increase.

One particularly encouraging bit of news is that at the state level, overdose declines are particularly steep in the states with the highest rates of mortality. Ohio and Pennsylvania, for instance, have so far seen decreases in the neighborhood of 20 percent since mortality peaked in late 2017. West Virginia, the state with the nation’s highest rate of drug overdoses, has seen a decline of nearly 12 percent.

Overall, the CDC data show that 12-month drug overdoses declined in 20 states between April 2017 and April 2018.

Again, the CDC stresses that these numbers are provisional and should be treated with caution. But, so far, each of the past seven months has shown a decrease in overdose deaths, the first time that’s happened since the CDC began releasing this monthly data in 2015.