The all A (including A-) students get "Principal Award". I kind of figured that out by looking at the crowd who receive the award. Maybe not 20%, but certainly more than 10%.

When graduatued from middle school, students who got straight A in all subjects and in all 3 years receive another award (I don't remember the exact name, but let's call it perfect GPA award)). There were almost 20 students got the Perfect GPA Award in the year when my elder son graduated. That was out of 300-400 students.

But the middle school my son was at was a good school. Perfect GPA in high school is not as easy though.