http://www.thedp.com/article/2017/12/early-decision-upenn-ivy-league-philadelphia-admissions-rate
UPenn ED: Early Apps: 7,074, Admits: 1,312, Admit rate: 18.5%
https://www.thecrimson.com/article/2017/12/13/early-admissions-2022/
Harvard EA: Apps 6,630. Accepts 964 (14.5%)
https://www.princeton.edu/news/2017/12/13/princeton-offers-early-action-admission-799-students-class-2022
Princeton EA: Apps 5,402. Accepts 799 (14.7%)
https://admissionsintel.com/duke-early-decision-admissions-rate-drops-to-20-percent/
Duke ED: About 4000 Apps, About 850 Accepts, (just over 20%)
https://admissionsintel.com/mit-received-16-percent-more-early-action-applicants-this-fall/
MIT: About 9700 Apps, about 6.8% addmit rate.