for additional information on segment results see page 43 .income from equity method investments increased by $ 126 million in 2006 from 2005 and increased by $ 98 million in 2005 from 2004 .income from our lpg operations in equatorial guinea increased in both periods due to higher sales volumes as a result of the plant expansions completed in 2005 .the increase in 2005 also included higher ptc income as a result of higher distillate gross margins .cost of revenues increased $ 4.609 billion in 2006 from 2005 and $ 7.106 billion in 2005 from 2004 .in both periods the increases were primarily in the rm&t segment and resulted from increases in acquisition costs of crude oil , refinery charge and blend stocks and purchased refined products .the increase in both periods was also impacted by higher manufacturing expenses , primarily the result of higher contract services and labor costs in 2006 and higher purchased energy costs in 2005 .purchases related to matching buy/sell transactions decreased $ 6.968 billion in 2006 from 2005 and increased $ 3.314 billion in 2005 from 2004 , mostly in the rm&t segment .the decrease in 2006 was primarily related to the change in accounting for matching buy/sell transactions discussed above .the increase in 2005 was primarily due to increased crude oil prices .depreciation , depletion and amortization increased $ 215 million in 2006 from 2005 and $ 125 million in 2005 from 2004 .rm&t segment depreciation expense increased in both years as a result of the increase in asset value recorded for our acquisition of the 38 percent interest in mpc on june 30 , 2005 .in addition , the detroit refinery expansion completed in the fourth quarter of 2005 contributed to the rm&t depreciation expense increase in 2006 .e&p segment depreciation expense for 2006 included a $ 20 million impairment of capitalized costs related to the camden hills field in the gulf of mexico and the associated canyon express pipeline .natural gas production from the camden hills field ended in 2006 as a result of increased water production from the well .selling , general and administrative expenses increased $ 73 million in 2006 from 2005 and $ 134 million in 2005 from 2004 .the 2006 increase was primarily because personnel and staffing costs increased throughout the year primarily as a result of variable compensation arrangements and increased business activity .partially offsetting these increases were reductions in stock-based compensation expense .the increase in 2005 was primarily a result of increased stock-based compensation expense , due to the increase in our stock price during that year as well as an increase in equity-based awards , which was partially offset by a decrease in expense as a result of severance and pension plan curtailment charges and start-up costs related to egholdings in 2004 .exploration expenses increased $ 148 million in 2006 from 2005 and $ 59 million in 2005 from 2004 .exploration expense related to dry wells and other write-offs totaled $ 166 million , $ 111 million and $ 47 million in 2006 , 2005 and 2004 .exploration expense in 2006 also included $ 47 million for exiting the cortland and empire leases in nova scotia .net interest and other financing costs ( income ) reflected a net $ 37 million of income for 2006 , a favorable change of $ 183 million from the net $ 146 million expense in 2005 .net interest and other financing costs decreased $ 16 million in 2005 from 2004 .the favorable changes in 2006 included increased interest income due to higher interest rates and average cash balances , foreign currency exchange gains , adjustments to interest on tax issues and greater capitalized interest .the decrease in expense for 2005 was primarily a result of increased interest income on higher average cash balances and greater capitalized interest , partially offset by increased interest on potential tax deficiencies and higher foreign exchange losses .included in net interest and other financing costs ( income ) are foreign currency gains of $ 16 million , losses of $ 17 million and gains of $ 9 million for 2006 , 2005 and 2004 .minority interest in income of mpc decreased $ 148 million in 2005 from 2004 due to our acquisition of the 38 percent interest in mpc on june 30 , 2005 .provision for income taxes increased $ 2.308 billion in 2006 from 2005 and $ 979 million in 2005 from 2004 , primarily due to the $ 4.259 billion and $ 2.691 billion increases in income from continuing operations before income taxes .the increase in our effective income tax rate in 2006 was primarily a result of the income taxes related to our libyan operations , where the statutory income tax rate is in excess of 90 percent .the following is an analysis of the effective income tax rates for continuing operations for 2006 , 2005 and 2004 .see note 11 to the consolidated financial statements for further discussion. .
[['', '2006', '2005', '2004'], ['statutory u.s . income tax rate', '35.0% ( 35.0 % )', '35.0% ( 35.0 % )', '35.0% ( 35.0 % )'], ['effects of foreign operations including foreign tax credits', '9.9', '-0.8 ( 0.8 )', '0.5'], ['state and local income taxes net of federal income tax effects', '1.9', '2.5', '1.6'], ['other tax effects', '-2.0 ( 2.0 )', '-0.4 ( 0.4 )', '-0.9 ( 0.9 )'], ['effective income tax rate for continuing operations', '44.8% ( 44.8 % )', '36.3% ( 36.3 % )', '36.2% ( 36.2 % )']]
.

Question: by how much did the effective income tax rate for continuing operations increase from 2005 to 2006?
Answer: 8.5%