From some quick googling, it sounds like less than half of high-school students take the SAT. In which case the bottom end of the scores will probably tell you

From some quick googling, it sounds like less than half of high-school students take the SAT. In which case the bottom end of the scores will probably tell you nothing about the population. "3.8 million students took the PSAT -- the practice version of the SATs ... 1.7 million students from the class of 2015 took the SAT"