12 million was at the peak of the war, the number you want is at the start of the war, when Hitler felt he had enough troops to invade with.
I tried to quickly find the numbers, but had no luck. It was 100,000 in 1931 (scaled back from WW I) and was supposed to be tripled through recruitment before Hitler started conscription.
Sorry. I should have also linked to the numbers. I got the external link from the Wehrmacht wiki article: http://www.feldgrau.com/stats.html
That table has nothing older than 1939, but the number in 1939 was still pretty impressive.
I also got confused, the 12,000,000 peak is directly comparable to the recent 178,000 since "Wehrmacht" was the previous name for the complete "unified" armed forces, not just the army.
I tried to quickly find the numbers, but had no luck. It was 100,000 in 1931 (scaled back from WW I) and was supposed to be tripled through recruitment before Hitler started conscription.