Well, maybe it helps to compare:
Germany: 2155 homicides in 2011, 6 by the police.
Germany: 2155 homicides in 2011, 6 by the police.
http://www.dw.com/en/two-german-police-officers-killed-by-fl...
In most of Western Europe it's extremely rare that police officers are killed in the line of duty.
Note: most countries count the number of bullets fired by police, as well as number of times a weapon was drawn, in the US they don't officially count people killed.
http://m.rp-online.de/politik/studie-gewalt-gegen-polizisten...