FIDE Elo ratings of the participants.

FIDE Set To Make Significant Changes To Rating System From January - Chess .com

What are the average Elo and USCF ratings? - Chess Stack Exchange

Should Women's Chess Titles Be Eliminated?

At what age are chess players at their peak?

FIDE - Wikipedia

Infographic: Chess Players Titles and Ratings in 2019 - SparkChess

FIDE rating differences between countries - English Chess Forum

Distribution of Elo rating points among active chess players.

Player Rating Percentiles (Chess.com) : r/chess

Chess ratings of male & female players organized by proportion (src in comments) : r/chess

The Elo rating system – correcting the expectancy tables