war statistics are bull****.
they are taken over the period of the entire war.
this assumes that the war was a totally uniform event from start to finish.
well it wasn't.
during periods when an enemy has superiority the probability of a pilot meeting his demise is significantly higher than at periods when the enemy is beaten into submission.
the australian RAAF lasted two weeks into the pacific war and were totally wiped out. after resupply of aircraft, primarily by the USA, they rearmed and went on to a creditable effort. the overall statistics I'm sure will give no hint of the utter demise they suffered in the first two weeks.