Percentile is a relative measurement against the group of people who participate in the same test. Assume you are the only one who scored full marks in SSAT, then everyone else are below you in the 99% of the population which gives you the 99 percentile ranking. However, if I also scored full marks in the same test, then you and I are the top and we are both at 99 percentile. On the contrary, even if I tested well and got 90% of the questions correct, but unfortunately in that particular SSAT test, EVERYONE scored higher than me, then I am at 0 percentile! It is difficult to say how many students or Chinese students scores 99 percentile in each test or year because it all depends on how many achieve the same scores.。