On Base Percentage (OBP) 
Divide the total number of hits, bases on balls and times hit by pitch by the total of atbats, bases on balls, times hit by pitch and sacrifice flies. For example, if Shawn Green has 619 atbats, 184 hits, 72 bases on balls, 5 times hit by pitch and 5 sacrifice flies, his onbase percentage is .372 ((184+72+5)/(619+72+5+5)).
