For the German side I have this table copied from Van Creveld’s ‘’ Fighting power: German and US Army performance, 1939-1945’’ p66 ,source he gives is ‘’Das Heer ‘’.
Despite all the talk of Stalingrad being the death of the German army numerical strength in ’43 is way up compared to ’42 .In ’44 there is only a tiny drop in total manpower.The German army didn’t shrink during the war.On the other hand not increasing in size was fatal since the Allies and especially the Soviet Union almost doubled their forces.
Compare with losses ,taken from The Oxford companion to World War II p371 :
So the Germans could handle the losses and maintain their army BUT they could not increase it.A serious problem when you have a continent to keep under control and enemies with huge armies to fight.
For the UK side this data comes from ‘’The smoke and the fire: myths and anti-myths of war, 1861-1945’’ p219 by British historian John Terraine.
Notice the relative size of the Army versus Navy and RAF.
Finally the data for the Soviet side come from the standard book on the subject ‘’ Soviet Casualties and Combat Losses in the Twentieth Century’’ by Krivosheev.
Some observations : Number of missing goes down after ’42 , meaning the Germans cannot destroy enemy forces by encircling them ,at least not on the same scale as in the first and second year. Number of killed and wounded is always high.The year of worst losses for Soviet side is 1943.This makes sense as in ’44 half the German army will have to fight in France against the Anglo-Americans thus keeping Soviet losses down.
For some reason Krivosheev only gives strength data for the operational forces.Total numbers are shown in this post in Axis History Forum : http://forum.axishistory.com/viewtopic.php?f=79&t=83300&start=45
Hmm so when the German generals said they lost the war because of the Soviet Union’s inexhaustible supply of manpower maybe they weren’t lying…