They have perfect grades because of grade inflation. It's cruel that because the boundaries of what is tested have narrowed, those who wish to prove themselves must focus on perfection rather than mastery.
Then the grading system should be changed so it's not as easy to get perfect scores and a bunch of people aren't clustering at the top.
Somehow this is made to work in other countries. Many of them have competitive university entrance exams where people are ranked in order, and nobody or nearly nobody gets a perfect score.