Zach Levine has an interesting blog post on Michael Bourn's improvement from 2008 to 2009:
From the standpoint of sheer increase in OPS, he was one of the best. There were 199 players in baseball who had at least 324 plate appearances (two per game) in both 2008 and 2009, and of those, Bourn had the eighth highest increase in OPS.
In raising his OPS from .588 to .738, that's an increase in .150 points. Not just is that 8th best in the Majors, it's 3rd-highest in the NL, behind Troy Tulowitzki (who led the Majors with a +196, and Carlos Ruiz with a +160.)