<ARTICLE> 5
<LEGEND>
This schedule contains summary financial information extracted from the
Consolidated Balance Sheets and the Consolidated Statements of Earnings at the
date and for the period indicated and is qualified in its entirety by reference
to such financial statements.  All amounts shown are in thousands of dollars,
except per share data.
</LEGEND>
<MULTIPLIER> 1

                             
<PERIOD-TYPE>                   12-MOS
<FISCAL-YEAR-END>                          MAR-31-2000
<PERIOD-START>                             APR-01-1999
<PERIOD-END>                               MAR-31-2000
<CASH>                                         226,910
<SECURITIES>                                         0
<RECEIVABLES>                                  161,337
<ALLOWANCES>                                    12,331
<INVENTORY>                                     25,405
<CURRENT-ASSETS>                               403,693
<PP&E>                                       1,398,651
<DEPRECIATION>                                 842,620
<TOTAL-ASSETS>                               1,432,336
<CURRENT-LIABILITIES>                           74,837
<BONDS>                                              0
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                         6,056
<OTHER-SE>                                   1,108,145
<TOTAL-LIABILITY-AND-EQUITY>                 1,432,336
<SALES>                                        574,815
<TOTAL-REVENUES>                               574,815
<CGS>                                          508,176
<TOTAL-COSTS>                                  508,176
<OTHER-EXPENSES>                                     0
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                                 714
<INCOME-PRETAX>                                105,208
<INCOME-TAX>                                         0
<INCOME-CONTINUING>                                  0
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                    76,590
<EPS-BASIC>                                       1.38
<EPS-DILUTED>                                     1.37