|                                                                          |   |                    |    |  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                                                    |   | $                       | 202,021 |         | $      | 282,865      |   | $ | 195,613 |   | $ | 166,801 |   | $ | 201,263 |   | $ | 203,381 |   | $ | 113,429 |   |
| Fixed Charges (as below)                                                      |   |                    | 118,365 |         |   | 151,874      |   |   | 178,067 |   |   | 225,573 |   |   | 215,640 |   |   | 215,964 |   |   | 54,359 |   |
| Total Earnings                                                                |   | $                       | 320,386 |         | $      | 434,739      |   | $ | 373,680 |   | $ | 392,374 |   | $ | 416,903 |   | $ | 419,345 |   | $ | 167,788 |   |
|                                                                          |   |                    |    |         |   |         |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| FIXED CHARGES                                                                 |   |                    |    |         |   |         |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Interest Expense                                                              |   | $                       | 106,301 |         | $      | 129,106      |   | $ | 165,405 |   | $ | 209,733 |   | $ | 202,426 |   | $ | 204,448 |   | $ | 51,727 |   |
| Credit for Allowance for Borrowed Funds Used    During Construction |   |                    | 8,764   |         |   | 17,668       |   |   | 6,962 |   |   | 9,040 |   |   | 6,014 |   |   | 4,316 |   |   | 832 |   |
| Estimated Interest Element in Lease Rentals                                   |   |                    | 3,300   |         |   | 5,100        |   |   | 5,700 |   |   | 6,800 |   |   | 7,200 |   |   | 7,200 |   |   | 1,800 |   |
| Total Fixed Charges                                                           |   | $                       | 118,365 |         | $      | 151,874      |   | $ | 178,067 |   | $ | 225,573 |   | $ | 215,640 |   | $ | 215,964 |   | $ | 54,359 |   |
|                                                                          |   |                    |    |         |   |         |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Ratio of Earnings to Fixed Charges                                            |   |                    | 2.70    |         |   | 2.86         |   |   | 2.09 |   |   | 1.73 |   |   | 1.93 |   |   | 1.94 |   |   | 3.08 |   |