<ARTICLE> OPUR1
<CIK> 0000318819
<NAME> R. D. SIEVERS

                             
<PERIOD-TYPE>                   3-MOS
<FISCAL-YEAR-END>                          DEC-31-2000
<PERIOD-END>                               MAR-31-2000
<BOOK-VALUE>                                  PER-BOOK
<TOTAL-NET-UTILITY-PLANT>                    4,993,041
<OTHER-PROPERTY-AND-INVEST>                    164,772
<TOTAL-CURRENT-ASSETS>                         266,123
<TOTAL-DEFERRED-CHARGES>                       335,290
<OTHER-ASSETS>                                 271,512
<TOTAL-ASSETS>                               6,030,738
<COMMON>                                       117,927
<CAPITAL-SURPLUS-PAID-IN>                      434,013
<RETAINED-EARNINGS>                          1,005,216
<TOTAL-COMMON-STOCKHOLDERS-EQ>               1,657,413
<PREFERRED-MANDATORY>                           73,609
<PREFERRED>                                     19,791
<LONG-TERM-DEBT-NET>                         2,421,236
<SHORT-TERM-NOTES>                             235,630
<LONG-TERM-NOTES-PAYABLE>                            0
<COMMERCIAL-PAPER-OBLIGATIONS>                       0
<LONG-TERM-DEBT-CURRENT-PORT>                   50,737
<PREFERRED-STOCK-CURRENT>                            0
<CAPITAL-LEASE-OBLIGATIONS>                          0
<LEASES-CURRENT>                                     0
<OTHER-ITEMS-CAPITAL-AND-LIAB>               1,572,322
<TOT-CAPITALIZATION-AND-LIAB>                6,030,738
<GROSS-OPERATING-REVENUE>                      307,759
<INCOME-TAX-EXPENSE>                            18,419
<OTHER-OPERATING-EXPENSES>                     217,311
<TOTAL-OPERATING-EXPENSES>                     235,730
<OPERATING-INCOME-LOSS>                         72,029
<OTHER-INCOME-NET>                               1,800
<INCOME-BEFORE-INTEREST-EXPEN>                  73,829
<TOTAL-INTEREST-EXPENSE>                        46,746
<NET-INCOME>                                    27,083
<PREFERRED-STOCK-DIVIDENDS>                        996
<EARNINGS-AVAILABLE-FOR-COMM>                   26,087
<COMMON-STOCK-DIVIDENDS>                        21,900
<TOTAL-INTEREST-ON-BONDS>                       43,529
<CASH-FLOW-OPERATIONS>                          58,150
<EPS-BASIC>                                       0.27
<EPS-DILUTED>                                     0.27