Bre901,
Yes, that's exactly the figure I found in Collins/Jane's Aircraft of World War II, published in 1995, describing the Il-2 as "the most produced aircraft in history".
However, I don't doubt the figures for the 172 so I guess it's a toast of vodka and bourbon to all of you. By the way I was really surprised to learn about the Shturmovik. I never would have guessed that the Russians produced so many planes.