Just to point out*, even if we get accurate numbers of NSDAP membership, those are not accurate indicators of being Nazis - people agreed with the Nazis on most ideology without automatically becoming party members, and in other branches at least, people often joined the Nazi union group (Lehrerbund - teachers organisation etc.) in order to keep their job during lay-offs, but without believing the whole ideology.
My general impression, for example from reading von Gersdorff memories, was that the officers of the Reichswehr were firmly apolitical - although with a conservative- rightwing tendency in ideology, they refrained from participating or making statements about politics during the turmoil years.
Afterwards, a number of officers still belonged to the nobility and came from a long military tradition and considered themselves professional soldiers. Their shock at the atrocities they witnessed on the Eastern front was one of the two major reasons for the people from the Kreisauer Kreis to contemplate breaking their personal oath and try to assassinate Hitler. (The other major reason was that his complete ineptitude in military leadership lead to thousands of German soldiers - for which the officers did feel responsible - being killed needlessly).
- I’m sure you know that, but not everybody else might.