it's probably a really high percentile, think about it that way: we're all humans and love to brag, so all the people that get high scores will post them right away! it just feel awesome telling others how smart we are by showing them crazy scores! but then you have all the 20 and below who think they have failed miserably (while they have actually scored like what most enrollees actually scored) and don't post their grades!
there are 12000 applicants each year, 5000 make it in dental school with averages of 19-20.. some had above that, others had below! I can't really tell how many out of these 5000 had 17,18,19,20,21,22,23,30, but I am sure more than half scored around 19-20!