<p>I found the original source from 2005 and here is what it states:
“Now examine Harvard admissions. The probability of admission rises from close to zero at the 88th percentile to about 10 percent at the 93rd percentile. It then increases very gradually to the 98th percentile, and finally rises steeply to 20 percent. In other words, if every student admitted to Harvard matriculated, then Harvard would have a class in which 35 percent of students came from the 99th percentile and above, about 55 percent of students came from the 94th through the 98th percentile, and the remaining 10 percent of students came from the 93rd percentile and below. Now examine Yale, which displays a very slight non-monotonicity: the probability of admission rises up through the 93rd percentile, then falls just a bit, and finally rises steeply above the 97th percentile. Finally, examine Princeton, which displays more non-monotonicity. Its probability of admission rises to 20 percent at the 93 percentile, falls to 10 percent at the 98 percentile, and then rises steeply in the top 2 percentiles.”
So it really is a N-shaped curve, not a bell shaped curve. Somehow the dip in the middle left a stronger impression in my mind than the uptick at the very end of the curve.</p>