Why high acceptance rates at some top art schools?

I know that School of the Art Institute of Chicago and Pratt are considered top art schools, but I looked at their acceptance rates and chicago has 81% and Pratt is at 42%. I was expecting at least under 30%. Can someone explain this to me?

My brother graduated from SAIC. I hear it is very difficult to get accepted. He tried three times before he was finally accepted. I don’t know much about Pratt.