Massachusetts opioid overdose deaths through September have declined about 10 percent year-over-year, though fatalities remain well above the state's historical norm.

An estimated 1,470 people died from opioid-related overdoses in the first nine months of 2017, the state said Monday. That number is higher than the total number of deaths in 2014, but marks an improvement from the estimated 1,637 deaths from January to September of last year.

''This new report shows some trend lines that are moving in the right direction as we work to fight the opioid and heroin epidemic in Massachusetts, but there are still too many people dying from overdoses,'' Gov. Charlie Baker said in a statement. ''Our administration will continue efforts to combat this public health epidemic that is devastating families in every corner of the Commonwealth, and looks forward to introducing new proposals in the near future and working with the Legislature to pass meaningful reform to strengthen our efforts from prevention to recovery."

It is the second quarterly opioid report that shows a year-over-year drop in overdoses -- a signal that the fever may have broken, and that the state may be on track for its first year of declining overdose deaths since 2010.

The report also shows that the synthetic opioid fentanyl has continued to be a driver of overdose deaths in Massachusetts.

Fentanyl, which is dozens of times more potent than heroin, has increased its presence on Massachusetts streets in recent years. While fentanyl was originally designed as a medical drug when it was developed in the 1950s, it has since become a popular additive to street heroin due to its low cost and potency.

It has also become a killer in Massachusetts, with fentanyl present in the toxicology screens of 81 percent of fatal overdose victims this year -- up from 66 percent in the second quarter of 2016.

Due to its cheapness and potency, drug distributors often cut heroin with fentanyl before it is sold on the street. That can lead to unexpectedly strong batches of heroin that cause localized spikes in overdoses, public safety officials have said.

The report also shows decreases in the number of people prescribed schedule II opioids and a decline in the number of overdoses linked to prescription drugs.

The Governor's Office pointed to steps the state has taken to address the crisis, including increasing substance abuse prevention and treatment funding, limiting first-time opioid prescriptions and strengthening the monitoring of prescription opioids.