expenditures and acquisitions of leased properties are funded by the original contributor of the assets , but no change in ownership interest may result from these contributions .an excess of ashland funded improvements over marathon funded improvements results in a net gain and an excess of marathon funded improvements over ashland funded improvements results in a net loss .cost of revenues increased by $ 8.718 billion in 2003 from 2002 and $ 367 million in 2002 from 2001 .the increases in the oerb segment were primarily a result of higher natural gas and liquid hydrocarbon costs .the increases in the rm&t segment primarily reflected higher acquisition costs for crude oil , refined products , refinery charge and blend feedstocks and increased manufacturing expenses .selling , general and administrative expenses increased by $ 107 million in 2003 from 2002 and $ 125 million in 2002 from 2001 .the increase in 2003 was primarily a result of increased employee benefits ( caused by increased pension expense resulting from changes in actuarial assumptions and a decrease in realized returns on plan assets ) and other employee related costs .also , marathon changed assumptions in the health care cost trend rate from 7.5% ( 7.5 % ) to 10% ( 10 % ) , resulting in higher retiree health care costs .additionally , during 2003 , marathon recorded a charge of $ 24 million related to organizational and business process changes .the increase in 2002 primarily reflected increased employee related costs .inventory market valuation reserve is established to reduce the cost basis of inventories to current market value .the 2002 results of operations include credits to income from operations of $ 71 million , reversing the imv reserve at december 31 , 2001 .for additional information on this adjustment , see 201cmanagement 2019s discussion and analysis of critical accounting estimates 2013 net realizable value of inventories 201d on page 31 .net interest and other financial costs decreased by $ 82 million in 2003 from 2002 , following an increase of $ 96 million in 2002 from 2001 .the decrease in 2003 is primarily due to an increase in capitalized interest related to increased long-term construction projects , the favorable effect of interest rate swaps , the favorable effect of interest on tax deficiencies and increased interest income on investments .the increase in 2002 was primarily due to higher average debt levels resulting from acquisitions and the separation .additionally , included in net interest and other financing costs are foreign currency gains of $ 13 million and $ 8 million for 2003 and 2002 and losses of $ 5 million for 2001 .loss from early extinguishment of debt in 2002 was attributable to the retirement of $ 337 million aggregate principal amount of debt , resulting in a loss of $ 53 million .as a result of the adoption of statement of financial accounting standards no .145 201crescission of fasb statements no .4 , 44 , and 64 , amendment of fasb statement no .13 , and technical corrections 201d ( 201csfas no .145 201d ) , the loss from early extinguishment of debt that was previously reported as an extraordinary item ( net of taxes of $ 20 million ) has been reclassified into income before income taxes .the adoption of sfas no .145 had no impact on net income for 2002 .minority interest in income of map , which represents ashland 2019s 38 percent ownership interest , increased by $ 129 million in 2003 from 2002 , following a decrease of $ 531 million in 2002 from 2001 .map income was higher in 2003 compared to 2002 as discussed below in the rm&t segment .map income was significantly lower in 2002 compared to 2001 as discussed below in the rm&t segment .provision for income taxes increased by $ 215 million in 2003 from 2002 , following a decrease of $ 458 million in 2002 from 2001 , primarily due to $ 720 million increase and $ 1.356 billion decrease in income before income taxes .the effective tax rate for 2003 was 36.6% ( 36.6 % ) compared to 42.1% ( 42.1 % ) and 37.1% ( 37.1 % ) for 2002 and 2001 .the higher rate in 2002 was due to the united kingdom enactment of a supplementary 10 percent tax on profits from the north sea oil and gas production , retroactively effective to april 17 , 2002 .in 2002 , marathon recognized a one-time noncash deferred tax adjustment of $ 61 million as a result of the rate increase .the following is an analysis of the effective tax rate for the periods presented: .
[['', '2003', '2002', '2001'], ['statutory tax rate', '35.0% ( 35.0 % )', '35.0% ( 35.0 % )', '35.0% ( 35.0 % )'], ['effects of foreign operations ( a )', '-0.4 ( 0.4 )', '5.6', '-0.7 ( 0.7 )'], ['state and local income taxes after federal income tax effects', '2.2', '3.9', '3.0'], ['other federal tax effects', '-0.2 ( 0.2 )', '-2.4 ( 2.4 )', '-0.2 ( 0.2 )'], ['effective tax rate', '36.6% ( 36.6 % )', '42.1% ( 42.1 % )', '37.1% ( 37.1 % )']]
( a ) the deferred tax effect related to the enactment of a supplemental tax in the u.k .increased the effective tax rate 7.0 percent in 2002. .

Question: by how much did the effective tax rate decrease from 2002 to 2003?
Answer: -5.5%