[KarlInOhio]

This is the toughest Senate class to pick up ten seats in because the Republicans already hold the majority.

Class I, 2012 election, 21 D - 10 R - 2 I (but vote with the Dems)

Class II, 2014 election, 20 D - 13 R

Class III, 2010 election, 16 D - 18 R

[OldDeckHand]

Ping to this post - karlinohio explains it more effectively than I did.