Anand is about 100 Elo points weaker than Carlsen at all time controls. It's impressive that Anand is still #15 at his age (50 years), but he's the only 50-year-old at that elite level (2700+ Elo).

The age distribution of the top 100 Classical players is:

    16-19: 5
    20-29: 39
    30-39: 40
    40-49: 12
    50-51: 4

The 20s and 30s are really the peak ages for chess.