I'm also way to lazy to figure that out and even if I wasn't math is not my thing.
I had a similar question along those lines: Which sororities are in which tier, who has the most memebers. Basically stats nationally. I tried searching and I only come up with indvidual campuses.
Is there a web site with all of this on it, I tried
www.npcwomen.com but couldn't find it there.