<TABLE> <S> <C>
<PAGE>
<ARTICLE> UT
<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> 587,487
<OTHER-PROPERTY-AND-INVEST> 2,547
<TOTAL-CURRENT-ASSETS> 152,602
<TOTAL-DEFERRED-CHARGES> 37,271
<OTHER-ASSETS> 69,972
<TOTAL-ASSETS> 849,879
<COMMON> 51,418
<CAPITAL-SURPLUS-PAID-IN> 43,233
<RETAINED-EARNINGS> 188,151
<TOTAL-COMMON-STOCKHOLDERS-EQ> 282,802
21,438
0
<LONG-TERM-DEBT-NET> 210,000
<SHORT-TERM-NOTES> 0
<LONG-TERM-NOTES-PAYABLE> 0
<COMMERCIAL-PAPER-OBLIGATIONS> 53,847
<LONG-TERM-DEBT-CURRENT-PORT> 0
0
<CAPITAL-LEASE-OBLIGATIONS> 14,181
<LEASES-CURRENT> 703
<OTHER-ITEMS-CAPITAL-AND-LIAB> 266,908
<TOT-CAPITALIZATION-AND-LIAB> 849,879
<GROSS-OPERATING-REVENUE> 342,057
<INCOME-TAX-EXPENSE> 13,665
<OTHER-OPERATING-EXPENSES> 297,760
<TOTAL-OPERATING-EXPENSES> 311,425
<OPERATING-INCOME-LOSS> 30,632
<OTHER-INCOME-NET> 283
<INCOME-BEFORE-INTEREST-EXPEN> 30,915
<TOTAL-INTEREST-EXPENSE> 9,028
<NET-INCOME> 21,887
757
<EARNINGS-AVAILABLE-FOR-COMM> 21,130
<COMMON-STOCK-DIVIDENDS> 22,496
<TOTAL-INTEREST-ON-BONDS> 8,388
<CASH-FLOW-OPERATIONS> 109,546
<EPS-BASIC> 41.09
<EPS-DILUTED> 41.09
</TABLE>