More on admissions at the elite universities

In an earlier post, I remarked at the craziness of 93 percent of applicants being rejected at Harvard and Stanford.  Greg Mankiw posts this graphic from another source:

I am all the more convinced that it is not about the education itself, but is about the "brand name" ...

But, what was the story even ten years ago?  Mankiw adds this:

This is part of a longer-term trend.  Here are the admission rates from about 10 years before this graph begins:

Harvard: 12 %
Princeton: 14 %
Yale: 20 %
MIT: 27 %
Stanford: 19 %