Tri Sigma and Tri Delta had chapters there that closed (Tri Delta very recently), and Phi Sig and AST have never had a chapter there. Imagine if they got all 26 one day!
From the limited Formal IU Bid Day numbers given on the GreekChat NPC 2022-23 Recruitment Listings page, it's entirely likely more pnms were given bids this year than last.
Unfortunately, it appears those chapters deemed lower by students still aren't gaining an amount of new members equal to the number of new members gained by a majority of chapters .
I experienced a rush like that at Arkansas; they used to have bed rush. Huge numbers of women went unbid. One yearbook stated over half of the women rushing did not get bids.