With a third of the year complete, 2019 is shaping up to be the least deadly for police officers since 1965 – prompting one of America’s top law enforcement groups to say it’s holding its breath “hoping [that] the trend continues.”

The striking statistic, based on data from the Officer Down Memorial Page, which tracks the deaths of officers in the U.S. and its territories, comes amid a particularly tough week for law enforcement.

Four officers have died in the line of duty over the last seven days, bringing the total line of duty deaths for 2019 up to 40. The last time the overall number was at 40 on this day was 54 years ago -- in 1965 -- according to ODMP statistics. In 2018, there were already 63 officers who had died in the line of duty by May 10.

“We are holding our breaths and hoping the trend continues,” Jim Pasco, the executive director of the National Fraternal Order of Police, told Fox News. “We are watching as closely as anybody.”

OFFICERS KILLED IN THE LINE OF DUTY IN 2019

Robert McKeithen, a 24-year veteran of the Biloxi Police Department, was among the officers who lost their lives in the line of duty this week. (Biloxi Police Department)

Pasco says there are a number of possible reasons as to why the overall number of deaths is climbing at a slower rate this year than in decades past.

“We think that maybe one of the biggest factors here is not so much less violence against police, as it is improvements in medical technology,” he told Fox News. “This has come about in large part because of the number of trauma surgeons and professionals that have served in combat and dealt with the treatment of severe wounds.”

The FOP official says he believes one of the “unintended benefits” of people, especially medical professionals, experiencing combat “is improved expertise in dealing with medical emergencies.”

FAMILIES OF SERIOUSLY-INJURED POLICE OFFICERS SAY HEALTHCARE SYSTEMS ARE FAILING THEM

Pasco added: “one factor we have noticed that has come into play more and more over the last 15 years is improvements in training and protective equipment the officers have, as well as heightened awareness because of… unprovoked violence against police officers.”

Still, being a law enforcement officer is one of the deadliest jobs in America.

“The most dangerous things the officers do are to make a traffic stop or respond to a domestic disturbance,” Pasco said.

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And despite the lower number of police officers who have died in the line of duty so far in 2019, the numbers could spike at any time in the remaining months. Pasco says even though there has been some leveling off in recent years, the end of year totals have remained around the same.

Going back over the last five years, those totals were 163, 174, 174, 165 and 159, respectively. In 1965, the year 2019 is pacing, there ended up being 142 officers who were killed in the line of duty. The year 2012, in which 41 officers had died as of May 10, also ended with 142 overall deaths.