Yeah, it would definitely be a difficult statistic to find. A book that might be useful is
Atheists: A Groundbreaking Study of America's Nonbelievers. It's coauthored by Bob Altemeyer, who is a psychology prof here at the U of M. I flipped through it a while back at the university bookstore but have not seen it there since then. It doesn't appear to be at Dafoe but it is available at the Millennium Library downtown....I may swing by and pick it up this weekend.
