STOCK OPTION CALCULATION - EARNINGS PER SHARE Exhibit 11 - COMPUTATION OF PER SHARE EARNINGS (Thousands of dollars, except per share data) Six Months Ended June 30 Three Months Ended June 30 1995 1994 1995 1994 PRIMARY ---------------------------- ---------------------------- Average shares outstanding 31,117,222 30,890,262 31,155,318 30,922,092 Net effect of stock options - based on the treasury stock method using average market price (1) (1) (1) (1) ---------------------------- ---------------------------- 31,117,222 30,890,262 31,155,318 30,922,092 Net income (loss) $65,519 $28,380 $31,243 $20,634 Per-share amount $2.11 $0.92 $1.00 $0.67 ===== ===== ===== ===== FULLY DILUTED Average shares outstanding 31,117,222 30,890,262 31,155,318 30,922,092 Net effect of dilutive stock options - based on the treasury stock method using the average quarterly market price, if higher than exercise price 287,893 129,307 441,574 107,740 ---------------------------- ---------------------------- 31,405,115 31,019,569 31,596,892 31,029,832 Net income (loss) $65,519 $28,380 $31,243 $20,634 Per-share amount $2.09 $0.91 $0.99 $0.66 ===== ===== ===== ===== (1) Incremental number of shares excluded from calculation since they do not have a dilutive effect.