Here's one article on the subject. I haven't looked at the raw data, but according to this one article, in the Washington Post, during the 33 year period tracked, a population comprising about 12% of the US population, during the period tracked, was responsible for about 43% of all homicides against police.
If you take into account that the same segment of the population represents just 24% of all people killed by police, it would appear that tiny segment of the US population is winning it's war with the police.
Applying this statistic to the number of police officers killed on duty last year, approximately 20 police officers were killed by what's now 13% of the US population, during the same period in which 9 unarmed members of the 13% were killed by police of every race.
Yup. Looks like EBR's favorite team is running the board on the cops...but still whining like they're behind.