Just as a note, IU Panhel is in the process of expansion. Prior to this year they had 21 of the 26 Panhel Sororities and with the expansion this semester (DPhiE chosen over AST) they will have 22. The other three members of the PHC not on the campus are PhiSig, SK and Tri-Sig.
But with the numbers that went through this year, I'm not sure that even if they added all of the rest with similar sized houses that everyone would have gotten a bid.
http://bl-ids-website.ads.iu.edu/new....aspx?id=95066