Top tens in the Chessmetrics list (opens in new tab)

"I was intrigued to see the list of the youngest players to reach the top ten," said chess statistician Jeff Sonas. "As the article states, my monthly Chessmetrics historical ratings are indeed unofficial, but being able to look further back, more than a century before FIDE Elo ratings started, certainly does help to place the modern FIDE-rated players into a historical context for comparisons like this." Here is Jeff's historical data.