Defensive armament was certainly NOT one of the Luftwaffe bomber's strong points. This is not to say there was a lack of trying but they sure couldn't put down a defensive fire like the Allied bombers could.
Type Losses
Junkers Ju 87 74
Junkers Ju 88 281
Dornier Do 17 171
Dornier Do 215 6
Heinkel He 56 31
Heinkel He 111 246
Heinkel He 115 28
Henschel Hs 126 7
Messerschmitt Bf 109 533
Messerschmitt Bf 110 229
Total 1562
Crew positions aboard a Ju88 (typical):
Pilot - front left
Radio Operator/rear (upper) gunner - behind pilot: MG81J (2)
Bombadier/forward gunner - right front: MG81J (1)
Ventral gunner - sat behind Bombadier during flight, folded seat and entered ventral gun station during battle: MG81Z (1)
This would be more enlightening if we knew the relative numbers deployed of each type, /sortie loss rate would be more informative, but even then the type of ops and target location compared with defensive response would all have to be factored in?