Thank you for the info. I knew Hartmann fought on both fronts, but I didn't realize the balance was that skewed.
If you could do a graph for these things for each of the major combatants in WWII for the years 1939 - 1945 it would be revealing.
Actually for the US, you'd have to do two graphs...one for the Pacific and one for the European theaters.
The Japanese and British, for all intents and purposes, finished the war with the same aircraft they started (excepting the Gloster Meteor which essentially found its role killing V1s). After Coral Sea and Midway, Japanese pilot training programs could never replace the losses and institutional experience of their downed aviators. The US started the Pacific war in a dismal state with Brewster Buffalos, Wildcats, and few P-38s and P-40s. The ascendency of the Hellcat, Corsair and Thunderbolt turned the tables, and the US wisely rotated experienced combat pilots home to train new aviators. In Europe, Germany continued to increase the quality and effectiveness of its aircraft finishing out the war with the Me262 and Fw190, but their pilot losses and low manufacturing numbers couldn't keep pace. Similarly, I think a lot of Mustang pilots probably would have racked up even higher numbers if they had not been purely dedicated so much of the time to deep bomber escort missions and given a longer leash for purely tactical operations.
I think there are a lot of reasons for the disparity you cite, but I think it also has a lot to do with the kind of aviators flying for the respective powers and how that was phased as they transitioned from fighting defensive to offensive wars or vice versa over the course of WWII, superimposed over what they happened to be flying at the time.