Amid staggering numbers of fatal US drug overdoses, fewer people started using heroin in 2017 — the numbers dropping by more than half — a new federal survey suggests.

The Substance Abuse and Mental Health Services Administration (SAMSHA) on Friday released its long-running National Survey on Drug Use and Health (NSDUH), which surveys illicit drug use nationwide.

The yearly survey’s results are the vital signs of a nationwide drug overdose epidemic that killed around 70,000 people last year and was declared a national public health emergency by President Trump.

About 44,000 of those deaths came from heroin and related synthetic opioids such as fentanyl, which is many times more potent with notorious overdose risks. According to the group, which surveyed more than 60,000 people, there are about 500,000 people in the US who are users of heroin.

It’s possible that these high fatal overdose numbers are starting to sink in with illicit drug users. Last year, the number of new heroin users in the US dropped by 53% to 81,000 people, according to the survey’s findings. That’s down from 170,00 in 2016.

The survey also found “a significant increase” in people receiving specialty treatment for illicit drug use disorders. “This was particularly evident for those with heroin use disorder and opioid use disorders,” according to a SAMSHA summary of the findings.

“Great news,” medical epidemiologist Daniel Ciccarone of the University of California, San Francisco, told BuzzFeed News.

Drug users aren’t happy with the increase in fentanyl — a highly potent synthetic opioid that’s often mixed into heroin and is the cause of many overdoses — showing up in their drug supply, which could lead to fewer people starting on heroin in the first place, he added.

While deadly drugs like fentanyl can discourage new drug users, these opioid drugs are also responsible for strong physical dependencies in existing users, making it harder to kick the habit. This could extend the duration of the current overdose epidemic far longer than we’ve seen with previous epidemics.

“Availability of treatment is a crucial factor,” Ciccarone said, in allowing a decline in the overdose epidemic to take hold. Only about 1 in 3 people in drug treatment programs receive medication-assisted treatment, the most effective way to treat addiction disorders.

Some preliminary CDC data suggests that total drug overdoses have plateaued in the last year, driven by a decline in heroin and painkiller deaths; however, in the same time period, fentanyl deaths have continued to increase. A recent Blue Cross Blue Shield report found a 5% drop in clients reporting opioid use disorders as well.

Andrew Kolodny of Brandeis University told BuzzFeed News by email that the drop in new heroin users was “very good news,” not just for the sheer numbers, but also because it runs contrary to the theory that more people would turn to heroin as doctors became more cautious about prescribing opioid painkillers.

“The reason deaths have soared in illicit opioid users is because the illicit opioid supply became much more dangerous,” because of fentanyl, Kolodny said. “The new [survey] data makes this easier to see.”

While heroin use may be on a decline, there were some concerning upticks found in the survey. Methamphetamine use was found to be more popular among young adults 18 to 25 years old and pregnant women reported more opioid, cocaine, and marijuana use.

Despite it looking like things are heading in the right direction with the drop in new heroin users, the number of overdose fatalities remains “unacceptably high,” Ciccarone said.