Law enforcement fatalities nationwide rose to their highest level in five years in 2016, with 135 officers killed in the line of duty, according to preliminary data compiled and released today by the  National Law Enforcement Officers Memorial Fund  (NLEOMF) in their  2016 Law Enforcement Fatalities Report .

The 135 officer fatalities in 2016 are a 10 percent increase over the 123 who died in the line of duty last year and is the highest total since 2011 when 177 officers made the ultimate sacrifice.

Firearms-related incidents were the number one cause of death in 2016, with 64 officers shot and killed across the country. This represents a significant spike—56 percent—over the 41 officers killed by gunfire in 2015. Of the 64 shooting deaths of officers this year, 21 were the result of ambush-style attacks—the highest total in more than two decades. Eight multiple-shooting death incidents claimed the lives of 20 officers in 2016, tied with 1971 for the highest total of any year since 1932. Those incidents included five officers killed in ambush attacks in Dallas (TX) and three in Baton Rouge (LA) spanning 10 days in July.

Fifty-three officers were killed in traffic-related incidents in 2016, which was 10 percent more than the 48 killed on roadways in 2015. Of the 53 traffic-related deaths, 28 died in automobile crashes, 15 were struck and killed while outside of their vehicle and 10 were killed in motorcycle crashes. Prior to 2016, traffic-related incidents have been the number one cause of officer fatalities in 15 of the last 20 years.

Eighteen officers died from other causes in 2016, including 11 who died from job-related illnesses—mostly heart attacks—while performing their duties. Other causes included beatings (3), a drowning, a fall, an aircraft crash and a stabbing.

Among the states, Texas had the highest number of officer fatalities, with 17, followed by California with 10, Louisiana with nine, Georgia with eight, and Michigan with six. Six Federal law enforcement officers died in the line of duty in 2016, along with four from the U.S. territory of Puerto Rico and one tribal officer.

Six of the fallen officers in 2016 were female. Among the officers who died this year, the average age was 40, and the average length of service was 13 years.

"Public safety is a partnership and, too often, the service and sacrifice of our law enforcement professionals is taken for granted," observed NLEOMF President and CEO Craig W. Floyd. "We must never forget that 900,000 law enforcement officers nationwide risk their lives every day for our safety and protection. And, this year, 135 of those men and women did not make it home to their families at the end of their shift. As we begin the new year, let us all resolve to respect, honor, and remember those who have served us so well and sacrificed so much in the name of public safety."

There are currently 20,789 names of officers killed in the line of duty inscribed on the National Law Enforcement Officers Memorial in Washington, DC, dating back to the first known death in 1791. Over the past decade (2006-2015) the average annual number of officer fatalities has been 151. The deadliest year on record for law enforcement was 1930 when 307 law enforcement officers were killed in the line of duty. The last time officer fatalities dipped below 100 for a single year was 1944.

The statistics released are based on preliminary data compiled by the NLEOMF and do not represent a final or complete list of individual officers who will be added to the National Law Enforcement Officers Memorial in 2016. For a complete copy of the preliminary  2016 Law Enforcement Fatalities Report , go to:  www.LawMemorial.org/FatalitiesReport .