The what I love about these tennis players, man, I get older and … so do they.

It’s no secret that the game of professional tennis has skewed older in recent years, with Roger Federer and Serena Williams staying at the top of their games into their mid-30s, teenagers hardly making a dent on the ATP and women frequently breaking into the WTA’s top 10 around age 28, almost double the age when such breakouts used to happen.

In the days of Chrissie Evert, Tracy Austin, Steffi Graf and Monica Seles, it was routine for girls who didn’t have their driver’s license to occupy spots in the top 10. Men always tended to skew older, but still had young stars, such as Boris Becker winning Wimbledon at 17 and, somewhat recently, Rafael Nadal winning the French Open at age 19.

Consider:

Men’s Facts

1. In 1992 the average age of the men’s top 10 was 23.2 years.

In 2002 it was 24.5 years.

In 2015 it’s 28.6 years.

2. In the latest rankings, only one player (24-year-old Milos Raonic) is younger than the average age from just 13 years ago.

3. On the men’s side, there have been 10 teenage Grand Slam winners (including multiple winners such as Boris Becker and Mats Wilander). Right now there are just four teenagers in the top 100 and the furthest any of them has gotten in a Grand Slam is to the third round. Half of those players either have zero or one wins in a major.

4. There is one teenager currently in the top 75. There were six players ranked that high 30 years ago, including two in the top 10.

5. On the flip side, there were three players over the age of 28 in the top 40 back in 1985. This year, 18 of the top 25 are that old and 24 of the top 40 are over 28.

6. In 1995, the highest ranked 32-year-old man was No. 124 in the world and only eight men of that age were ranked in the top 500. Right now, 18 players that old are ranked higher than No. 124, including five in the top 25 (and the world No. 3, Federer)

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7. As recently as a decade ago, there were seven players aged 32 or above in the top 100. The 20th ranked player who was 32+ was ranked No. 676. Today, there are 12 players in the top 100 and the 20th ranked player that old is No. 192.

8. Of the 20 youngest Grand Slam winners, only five have won that major since 2005. The last teenager to win one was Rafael Nadal, who turned 19 while winning the 2005 French Open.

Women’s Stats

9. In 1992 the average age of the women’s top 10 was 21.7 years.

In 2002 it was 22.0 years.

In 2014 it’s 25.9 years.

10. In the latest rankings, only one player (21-year-old Garbine Muguruza) is younger than the average age of top 10ers from 2002.

11. Serena Williams became the oldest woman to ever win a Grand Slam when she took the title at Wimbledon and of course, she shows precisely zero signs of slowing down.

12. In 1990, half the women in the year-end top 10 were teenagers during that season. Currently, there are only three teenagers in the top 100.

13. Also in 1990, 20 women in the top 30 were under 23 years old. Currently, there are six players in the top 30 who are younger than 23.

14. Eight women have won Grand Slams before turning 19. This year, there is only one such teenager ranked in the entire top 150 (Ana Konjuh at No. 81).

15. This year, there are 15 women over 30 in the top 100. In 2000, there were two such women.

16. This one’s insane: In 2012 — just three years ago — there were three women over 32 in the top 100. This year there are eight.

17. Five of the seven oldest women to win their first Grand Slam have won it in the past decade. Of the 19 youngest women to win their first Slam, only one (Ana Ivanovic at age 20) has done that in the past 10 years.

Okay, so now that we’ve established the old is the new young, what is it? What’s making tennis players get better later and stay better when players from a decade ago were already retired?

It’s a question with a number of answers, all that probably contribute in one way or another. Could it be the combination of added power in the sport (the serve-and-volley is mostly dead), aided by racquet and string technology? Do training methods and diet help keep the top players healthier and in better shape? Has recovery — a key component when trying to win a match a day or seven matches in two weeks — become more of a science and something taken more seriously by players?

Whatever it is, the sport has never been older. Next month, Serena Williams will attempt to both tie Steffi Graf’s record of 22 Grand Slams while becoming the first player since Graf to win the calendar Slam. She’ll be doing that all at age 33.

By the time she was 33, Graf, who twice played Serena, had already been retired for three years.