percentile queery

It's simple. Portion of whole divided by the whole. In this case it's players who are worse than you divided by total number of players. 99 percentile means you're better than 99% of all players counted. In this case that means chess.com, or if looking at your national rating on a different website, then it would be among chess players in your nation. 50% means you're better than half. 20% means you're better than one fifth. etc.

it does seem simple when you explain it !Would you guess that Chess.com members are a fair reflection of chess players as a whole .do you in fact think online players differ a great deal from over the board .Just a thought but many thanks for your reply