EXHIBIT 12

COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES

	Three Months Ended
	Mar. 31		Mar. 31
	2006		2005
	(Thousands of dollars, except ratio amounts)
Income before income taxes	$	95,413	$	90,949
Share of undistributed losses from 50%-or-less-owned affiliates, excluding affiliates with guaranteed debt		688		1,135
Amortization of capitalized interest		322		322
Interest expense		13,065		12,675
Interest portion of rental expense		400		669
Earnings	$	109,888	$	105,750
Interest	$	13,266	$	12,785
Interest portion of rental expense		400		669
Interest expense relating to guaranteed debt of 50%-or-less-owned affiliates		—		—
Fixed Charges	$	13,666	$	13,454
Ratio of Earnings to Fixed Charges		8.04		7.86