Operations and summary of significant accounting policies D. Inventories Inventories are stated at the lower of cost or market . Cost is principally determined using the last - in , first - out ( LIFO ) method . The value of inventories on the LIFO basis represented about 75 % of total inventories at December 31 , 2006 and about 80 % of total inventories at December 31 , 2005 and 2004 . If the FIFO ( first - in , first - out ) method had been in use , inventories would have been $ 2,403 million , $ 2,345 million and $ 2,124 million higher than reported at December 31 , 2006 , 2005 and 2004 , respectively . 12 . Intangible assets and goodwill ... Amortization expense related to intangible assets was $ 34 million , $ 22 million and $ 18 million for 2006 , 2005 and 2004 , respectively ... ... During the first quarter of 2006 , we determined that the business outlook for the parts and accessories distribution business of MG Rover , acquired in 2004 , required a specific impairment evaluation . The declining outlook of this business resulted from MG Rover