'Better players peak earlier in their careers. While the general population peaks at age 27, the group of good players peak at either 25 or 26 years old. Hall-of-famers don’t usually peak — instead, they plateau. From ages 24 to 30, their production is generally constant. From then on, it drops at a high rate.' http://www.fangraphs.com/blogs/how-do-star-hitters-age/