@jaecha according to this parchment has a big representation in the midwest.
https://www.nytimes.com/interactive/2014/09/04/upshot/college-picks.html?_r=0#s=1519
The study done in this link is all over the place because of the very small sample sizes but it you scroll all the way down there is a map of parchment utilization in each state in 2014. It seems that in the midwest parchment is used more than in the east.
Yield rates are another way to get an idea of admit preference, especially RD yields (Class of 2020):
Penn(50.5%)
Cornell(41%)
NU (35%)
But yes i greek all excellent schools, choice comes more down to fit than anything.