NFL: 3.3 years.

PGA: 4 years.

NBA: 4.9 years.

NHL: 5 years.

MLB: 5.6 years.

Soccer: 8 years.

ATP: 9-10 years.

Boxers: 16.7 years.

Cricket: The typical major one now lasts 12 to 15 years for a batsman, about 10 for a bowler.