|                                                                          |   |                    |    | Twelve       |   |  Three  |   |
|-------------------------------------------------------------------------------|--------|-------------------------|---------|--------------|--------|--------------|--------|
|                                                                          |   |                    |    |  Months |   |  Months |   |
|                                                                          |   | Year Ended December 31, |    |  Ended  |   |  Ended  |   |
|                                                                          |   | 2005                    |    | 2006         |   | 2007         |   | 2008 |   |   | 2009 |   |  3/31/2010 |   |  3/31/2010 |   |
| EARNINGS                                                                      |   |               |    |    |   |    |   |    |   |   |   |   |   |   |   |   |   |   |
| Income Before Income Taxes                                                    |   | $                       | 199,259 |         | $      | 286,422      |   | $ | 387,473 |   | $ | 346,869 |   | $ | 415,382 |   | $ |  422,314 |   | $ |  79,901 |   |
| Fixed Charges (as below)                                                      |   |                    | 63,665  |         |   | 74,155       |   |   | 86,900 |   |   | 109,245 |   |   | 109,152 |   |   |  108,790 |   |   |  26,269 |   |
| Total Earnings                                                                |   | $                       | 262,924 |         | $      | 360,577      |   | $ | 474,373 |   | $ | 456,114 |   | $ | 524,534 |   | $ | 531,104 |   | $ |  106,170 |   |
|                                                                          |   |                    |    |         |   |         |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| FIXED CHARGES                                                            |   |                    |    |         |   |         |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Interest Expense                                                              |   | $                       | 59,539  |         | $      | 66,100       |   | $ | 69,625 |   | $ | 92,068 |   | $ | 88,184 |   | $ |  89,175 |   | $ |  21,784 |   |
| Credit for Allowance for Borrowed Funds    Used During Construction |   |                    | 1,526   |         |   | 5,955        |   |   | 7,275 |   |   | 2,677 |   |   | 5,968 |   |   | 4,615 |   |   |  735 |   |
| Estimated Interest Element in Lease Rentals                                   |   |                    | 2,600   |         |   | 2,100        |   |   | 10,000 |   |   |  14,500 |   |   | 15,000 |   |   |  15,000 |   |   |  3,750 |   |
| Total Fixed Charges                                                           |   | $                       | 63,665  |         | $      | 74,155       |   | $ | 86,900 |   | $ | 109,245 |   | $ | 109,152 |   | $ |  108,790 |   | $ |  26,269 |   |
|                                                                          |   |                    |    |         |   |         |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Ratio of Earnings to Fixed Charges                                            |   |                    | 4.12    |         |   | 4.86         |   |   | 5.45 |   |   | 4.17 |   |   | 4.80 |   |   |  4.88 |   |   |  4.04 |   |