Exhibit No.                                 Description

   1.1**      Underwriting Agreement, dated May 14, 2012, between the Company and
              Citigroup Global Markets Inc., Credit Suisse Securities (USA) LLC, J.P.
              Morgan Securities LLC, Morgan Stanley & Co. LLC and RBS Securities
              Inc., as representatives of the several underwriters identified
              therein, in connection with the offer and sale of $250.0 million in
              aggregate principal amount of the Company's1.60% Senior Notes due 2015
              and $250.0 million in aggregate principal amount of the Company's 3.60%
              Senior Notes due 2022.

   4.1*       Indenture, dated as of May 17, 2012, between the Company and Union
              Bank, N.A., as trustee.

   4.2**      First Supplemental Indenture, dated as of May 17, 2012, between the
              Company and Union Bank, N.A., as trustee, with respect to the Company's
              1.60% Senior Notes due 2015.

   4.3**      Second Supplemental Indenture, dated as of May 17, 2012, between the
              Company and Union Bank, N.A., as trustee, with respect to the Company's
              3.60% Senior Notes due 2022.

   4.4**      Form of Global Note for the Company's 1.60% Senior Notes due 2015
              (included in Exhibit 4.2).

   4.5**      Form of Global Note for the Company's 3.60% Senior Notes due 2022
              (included in Exhibit 4.3).

   5.1**      Opinion of Vinson & Elkins L.L.P.

  12.1**      Computation of Ratio of Earnings to Fixed Charges.

  23.1**      Consent of Vinson & Elkins L.L.P. (included in Exhibit 5.1).

  99.1**      Press Release of the Company, dated May 14, 2012.