You may find some old material amoungst the Leavenworth Papers or CARL, ect...  I know my father refered to smaterial of that sort published as far back as the 1940s.

While I dont recall specific numbers from those old documents one item stands out.  The author criticised one or more evaluations of tooth to tail ratios as flawed as they did not allow for the use of civilians filling the same task in other armys.  ie:  The US army & USN placed nearly all its labor support personnel & technicians in uniform as members of the armed forces.  The Wehrmacht & Luftwaffe made use of the Todt organization and similar groups to accomplish the same tasks.  These people were not counted as part of the tail as they were not in a military uniform.   ie:  The Wehrmacht was able to send severely damaged or worn vehicals back to civilian establishments in Germany to be salvaged.  Thus reducing the load on the forward repair organizations. For he US and Britian this was not so easy and most of the heavy salavage work was done by mechanics in military uniform.  ie: The Wehrmacht had some heavy contruction units, but nothing on the scale of the Construction Battalions (CB or See Bee) of the USN. Much of that was accomplished by the Germans with conscript labor, often unpaid. 

Germany had a whole "Army" only dedicated to military engineering, (for any works required behind the frontline) that is why the Wehrmacht concentrated on specialised engineers for frontline service, for example pioneers specialised at trains,  special "anti-fortification-pioneers", and even "paratrooper-pioneers" that could be dropped together with Paratroopers.

 

Organisation Todt:

 

[XXXttp://en.wikipedia.org/wiki/Organisation_Todt ]

 

- Between 1938 and 1940, 1.75 million Germans were conscripted into labour service.

 

- By the end of 1944, of approximately 1.4 million labourers in the service of the Organisation Todt overall, 1% were Germans rejected from military service and 1.5% were concentration camp... prisoners; the rest were prisoners of war and compulsory labourers from occupied countries. All were effectively treated as slaves and existed in the complete and arbitrary service of a ruthless totalitarian state. Many did not survive the work or the war.