<TABLE> <S> <C>
<PAGE>
<ARTICLE> UT
<MULTIPLIER> 1,000
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-2000
<PERIOD-START> JAN-01-2000
<PERIOD-END> JUN-30-2000
<BOOK-VALUE> PER-BOOK
<TOTAL-NET-UTILITY-PLANT> 1,318,290
<OTHER-PROPERTY-AND-INVEST> 1,103,158
<TOTAL-CURRENT-ASSETS> 519,391
<TOTAL-DEFERRED-CHARGES> 1,099,752
<OTHER-ASSETS> 0
<TOTAL-ASSETS> 4,040,591
<COMMON> 73,119
<CAPITAL-SURPLUS-PAID-IN> 931,464
<RETAINED-EARNINGS> 960,479
<TOTAL-COMMON-STOCKHOLDERS-EQ> 1,017,750<F1>
0
248,248<F2>
<LONG-TERM-DEBT-NET> 1,422,987
<SHORT-TERM-NOTES> 0
<LONG-TERM-NOTES-PAYABLE> 3,194
<COMMERCIAL-PAPER-OBLIGATIONS> 0
<LONG-TERM-DEBT-CURRENT-PORT> 77,614
0
<CAPITAL-LEASE-OBLIGATIONS> 11,024
<LEASES-CURRENT> 755
<OTHER-ITEMS-CAPITAL-AND-LIAB> 1,259,019
<TOT-CAPITALIZATION-AND-LIAB> 4,040,591
<GROSS-OPERATING-REVENUE> 649,575
<INCOME-TAX-EXPENSE> 9,532<F3>
<OTHER-OPERATING-EXPENSES> 585,517
<TOTAL-OPERATING-EXPENSES> 585,517
<OPERATING-INCOME-LOSS> 64,058
<OTHER-INCOME-NET> 70,761
<INCOME-BEFORE-INTEREST-EXPEN> 134,819
<TOTAL-INTEREST-EXPENSE> 65,236<F4>
<NET-INCOME> 60,051
(542)
<EARNINGS-AVAILABLE-FOR-COMM> 60,593
<COMMON-STOCK-DIVIDENDS> 53,357
<TOTAL-INTEREST-ON-BONDS> 38,893
<CASH-FLOW-OPERATIONS> 130,289
<EPS-BASIC> 0.87
<EPS-DILUTED> 0.85
<FN>
<F1>Includes $(947,312) of Treasury Stock at cost.
<F2>Includes $11,420 of Preference Stock.
<F3>Non-operating Expense.
<F4>Includes $8,007 of Preferred and Preference Stock Dividends.
</FN>
</TABLE>
