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The year-end Top 10 South African Airways ATP Rankings feature three players 21-under, led by No. 2 Rafael Nadal and No. 3 Novak Djokovic (pictured).

Nadal is 21 and Djokovic is 20 while No. 8 Richard Gasquet is 21. The oldest player in the year-end Top 10 is 27-year-old Chilean Fernando Gonzalez, who finished No. 7.

The average age of players in the Top 10 is 24.1 years (see chart below), the youngest average of that group since 1994. No. 4 Nikolay Davydenko and World No. 1 Roger Federer are the next oldest players in the Top 10 at 26 years old. There are four players who are 25 -- No. 5 David Ferrer, No. 6 Andy Roddick, No. 9 David Nalbandian and No. 10 Tommy Robredo.

The average age of the Top 20 is 25.1 years, up from last year's mark of 23.6. The oldest player in the Top 20 is 31-year-old Spaniard Carlos Moya. British No. 1 Andy Murray, who finished a year-end best No. 11, is the second-youngest player at 20 years old, seven days older than Djokovic.

The charts below show the age breakdown of the 2007 year-end Top 20 and a historical comparison of the average age of the year-end Top 10 and Top 20: