Home Run Proficiency: Bonds, McGwire, Sosa.

Let's zero in on the big three bad boys of the steroid era.  There will be more in future posts on others.  Click this link to view data and graph.

My guess as to when they started juicing:
Barry Bonds 1999
Mark McGwire 1995
Sammy Sosa 1998.

However, the Home Run Proficiency rate does not show the sudden increase that might be expected. There are many instances of sharp increases by other players in the past.  Look at the data and decide for yourself.