Who Do Democrats Vote With More Often: Jeff Klein or John Sampson?

From NYPIRG’s Bill Mahoney:

Most of the Senators enrolled as Democrats voted the same way as Senator Klein more often than they voted the same way as Senator Sampson.

Klein is the head of the Independent Democratic Caucus, a breakaway group of four rogue Democrats. Sampson, of course, is the head of the other (regular?) Democratic Caucus.