Hmmm, I had to check and total them up on the schools website. What I found was that we have 25 sororities listed.
http://www.uiuc.edu/ro/panhellenic/chapters/
As for fraternities, there were 47 listed.
http://www.uiuc.edu/ro/IFC/chapters.htm
The numbers didn't include BGLOs, and I can't be certain about any underground ones or upcoming ones. I had heard rumors that ZTA was trying to come back on the campus, but I could be wrong.
This is definitely interesting. I had no idea that your greek system was that big!