Exhibit A

Transactions by Reporting Persons in the last 60 days.

Beneficial Ownership	Purchase or Sale	Quantity	Transaction Date	Price per Share (including commission)	How Effected
Relational Investors Mid-Cap Fund I, L.P.	Purchase	17,460	5/14/2012	63.95	Open Market
Relational Investors Mid-Cap Fund I, L.P.	Purchase	14,576	5/14/2012	64.66	Open Market
Relational Investors Mid-Cap Fund II, L.P.	Purchase	8,188	5/14/2012	63.95	Open Market
Relational Investors Mid-Cap Fund II, L.P.	Purchase	6,836	5/14/2012	64.66	Open Market
Relational Investors LLC	Purchase	4,298	5/14/2012	63.95	Open Market
Relational Investors LLC	Purchase	3,588	5/14/2012	64.66	Open Market
Relational Investors Mid-Cap Fund I, L.P.	Purchase	1,050	5/15/2012	65.92	Open Market
Relational Investors Mid-Cap Fund I, L.P.	Purchase	9,955	5/15/2012	65.99	Open Market
Relational Investors Mid-Cap Fund I, L.P.	Purchase	40,181	5/15/2012	66.35	Open Market
Relational Investors Mid-Cap Fund II, L.P.	Purchase	492	5/15/2012	65.92	Open Market
Relational Investors Mid-Cap Fund II, L.P.	Purchase	4,669	5/15/2012	65.99	Open Market
Relational Investors Mid-Cap Fund II, L.P.	Purchase	369	5/15/2012	66.35	Open Market
Relational Investors LLC	Purchase	258	5/15/2012	65.92	Open Market
Relational Investors LLC	Purchase	2,451	5/15/2012	65.99	Open Market
Relational Investors LLC	Purchase	17,820	5/15/2012	66.35	Open Market
Relational Investors Mid-Cap Fund I, L.P.	Purchase	44,908	5/16/2012	67.39	Open Market
Relational Investors Mid-Cap Fund II, L.P.	Purchase	412	5/16/2012	67.39	Open Market
Relational Investors LLC	Purchase	19,916	5/16/2012	67.39	Open Market
Relational Investors Mid-Cap Fund I, L.P.	Purchase	34,420	5/17/2012	66.48	Open Market
Relational Investors Mid-Cap Fund I, L.P.	Purchase	34,420	5/17/2012	65.91	Open Market
Relational Investors Mid-Cap Fund I, L.P.	Purchase	17,210	5/17/2012	65.99	Open Market
Relational Investors Mid-Cap Fund I, L.P.	Purchase	21,425	5/17/2012	65.75	Open Market
Relational Investors Mid-Cap Fund II, L.P.	Purchase	316	5/17/2012	66.48	Open Market
Relational Investors Mid-Cap Fund II, L.P.	Purchase	316	5/17/2012	65.91	Open Market
Relational Investors Mid-Cap Fund II, L.P.	Purchase	158	5/17/2012	65.99	Open Market
Relational Investors Mid-Cap Fund II, L.P.	Purchase	197	5/17/2012	65.75	Open Market
Relational Investors LLC	Purchase	15,264	5/17/2012	66.48	Open Market
Relational Investors LLC	Purchase	15,264	5/17/2012	65.91	Open Market
Relational Investors LLC	Purchase	7,632	5/17/2012	65.99	Open Market
Relational Investors LLC	Purchase	9,502	5/17/2012	65.75	Open Market
Relational Investors Mid-Cap Fund I, L.P.	Purchase	10,937	5/18/2012	65.10	Open Market
Relational Investors Mid-Cap Fund I, L.P.	Purchase	69,357	5/18/2012	64.15	Open Market
Relational Investors Mid-Cap Fund II, L.P.	Purchase	100	5/18/2012	65.10	Open Market
Relational Investors Mid-Cap Fund II, L.P.	Purchase	640	5/18/2012	64.15	Open Market
Relational Investors LLC	Purchase	4,851	5/18/2012	65.10	Open Market
Relational Investors LLC	Purchase	30,764	5/18/2012	64.15	Open Market
Relational Investors Mid-Cap Fund I, L.P.	Purchase	12,939	5/23/2012	63.55	Open Market
Relational Investors Mid-Cap Fund I, L.P.	Purchase	523	5/23/2012	62.91	Open Market
Relational Investors Mid-Cap Fund II, L.P.	Purchase	7,437	5/23/2012	63.55	Open Market
Relational Investors Mid-Cap Fund II, L.P.	Purchase	299	5/23/2012	62.91	Open Market
Relational Investors LLC	Purchase	4,590	5/23/2012	63.55	Open Market
Relational Investors LLC	Purchase	185	5/23/2012	62.91	Open Market