Nit. Elo ratings aren't based on a percentile system," like IQ. Elo of X is actually set such that that rating is 2 times worse than an Elo of X+100.<br><br>Edit: from <a href=""https://www.youtube.com/watch?v=hppbxV9C63g&amp;t=18m18s"">18:18</a> or so"