First overall breakdown

Since the June amateur draft began in 1965, certain positions have dominated.

4Yr indicates four-year colleges (although players can be drafted after their third year. HS is high school, and JC is two-year junior colleges. In 2006, Luke Hochevar (NA) was selected No. 1 overall after eschewing his senior season at Tennessee to play independent baseball.
Source: Baseball Reference
Table: theScore