Average blitz on chess.com is 1029
Average rapid is 1096
https://www.chess.com/leaderboard/live
If that seems low it's because... well, it is low. Average for tournament players is more like 1500-1600. Average for FIDE players would be more like 1900-2000 (because until relatively recently you couldn't even get a FIDE rating without being rated over a certain amount, I think 2200).
I just wondered if there is such a thing as an average grade? Would any of the chess authorities or even chess.com have any idea at all what the average grade is of all graded players?