For some, that may be self-inflicted.
Have you ever seen hard stats on that? I think the percentage is much higher than just 50%.
Given the nature of the site, I would imagine they are probably overly sympathetic towards classifying things as "line of duty" deaths. For example, i would think that most folks wouldn't classify having a heart attack as a "line of duty" death. So... I've separated out what appears to be deaths of officers purposefully caused (firearm related) as opposed to stuff that would happen to people regardless of lines of work. I'd also put serious money that the ones classified as "vehicular assault" were more likely accidents than purposeful killings. You'll note the number that are related to automobiles and such. It appears that being the tax collector for the welfare state is more dangerous than just about anything.
Line of Duty Deaths: 92
Aircraft accident: 1
Automobile accident: 21
Drowned: 2
Duty related illness: 1
Fall: 4
Gunfire (Accidental): 1
Heart attack: 13
Motorcycle accident: 4
Struck by vehicle: 6
Training accident: 2
Vehicle pursuit: 2
Bomb: 1
Fire: 1
Gunfire: 27
Stabbed: 1
Vehicular assault: 5
Line of Duty Deaths: 92
Aircraft accident: 1
Automobile accident: 21
Bomb: 1
Drowned: 2
Duty related illness: 1
Fall: 4
Fire: 1
Gunfire: 27
Gunfire (Accidental): 1
Heart attack: 13
Motorcycle accident: 4
Stabbed: 1
Struck by vehicle: 6
Training accident: 2
Vehicle pursuit: 2
Vehicular assault: 5
It would appear that actual 'firearm related' deaths of officers are higher than I thought. However, even if one were to add all this up together as actual "line of duty" deaths, then divide by the number of officers that we have out there, you're still looking at pretty paltry numbers, especially when you consider how much whining you hear about how dangerous the job is.