At all state buildings throughout New Jersey on Saturday, flags will fly at half-staff to recognize the passing of State Police Lt. William Fearon, who died Wednesday of cancer linked to his service on 9/11.

Fearon, who leaves behind a wife and three children, is the third New Jersey law enforcement officer to die in 2016 just because they were doing their job.

State Trooper Frankie Williams was killed Dec. 5 while responding to a report of an erratic driver on Route 55. In March, Trooper Sean Cullen was struck and killed by a vehicle while responding to a car fire along Route 295.

According to the National Law Enforcement Officers Memorial Fund, traffic-related incidents have caused the most line-of-duty deaths over the past 20 years nationwide.

Fifty-three officers across the country were killed in traffic-related incidents in 2016, a 10 percent spike from 2015, NLEOMF said.

At 135, the overall line-of-duty fatality count, which is tracked each year by NLEOMF, hit its highest level in five years. The tally does not include Fearon's passing but his name is expected to be included once all the proper paperwork is submitted.

Firearms were the No. 1 cause of death nationally: 64 officers were shot and killed.

"Twenty-one of those officers were ambushed, meaning they were shot and killed simply because of the job that they do and the uniform that they wear," said NLEOMF President Craig Floyd.

In May, all of 2016's fallen officers' names will be added to the National Law Enforcement Officers Memorial in Washington, D.C. More than 60 deaths this year are related to illnesses suffered while responding to the 9/11 attacks.

Just under 500 law enforcement officers were killed in the line of duty throughout New Jersey's history.

More from New Jersey 101.5:

Contact reporter Dino Flammia at dino.flammia@townsquaremedia.com.