item 7 . management 2019s discussion and analysis of financial condition and results of operations we are an international energy company with operations in the u.s. , canada , africa , the middle east and europe . our operations are organized into three reportable segments : 2022 e&p which explores for , produces and markets liquid hydrocarbons and natural gas on a worldwide basis . 2022 osm which mines , extracts and transports bitumen from oil sands deposits in alberta , canada , and upgrades the bitumen to produce and market synthetic crude oil and vacuum gas oil . 2022 ig which produces and markets products manufactured from natural gas , such as lng and methanol , in eg . certain sections of management 2019s discussion and analysis of financial condition and results of operations include forward-looking statements concerning trends or events potentially affecting our business . these statements typically contain words such as 201canticipates , 201d 201cbelieves , 201d 201cestimates , 201d 201cexpects , 201d 201ctargets , 201d 201cplans , 201d 201cprojects , 201d 201ccould , 201d 201cmay , 201d 201cshould , 201d 201cwould 201d or similar words indicating that future outcomes are uncertain . in accordance with 201csafe harbor 201d provisions of the private securities litigation reform act of 1995 , these statements are accompanied by cautionary language identifying important factors , though not necessarily all such factors , which could cause future outcomes to differ materially from those set forth in forward-looking statements . for additional risk factors affecting our business , see item 1a . risk factors in this annual report on form 10-k . management 2019s discussion and analysis of financial condition and results of operations should be read in conjunction with the information under item 1 . business , item 1a . risk factors and item 8 . financial statements and supplementary data found in this annual report on form 10-k . spin-off downstream business on june 30 , 2011 , the spin-off of marathon 2019s downstream business was completed , creating two independent energy companies : marathon oil and mpc . marathon shareholders at the close of business on the record date of june 27 , 2011 received one share of mpc common stock for every two shares of marathon common stock held . fractional shares of mpc common stock were not distributed and any fractional share of mpc common stock otherwise issuable to a marathon shareholder was sold in the open market on such shareholder 2019s behalf , and such shareholder received a cash payment with respect to that fractional share . a private letter tax ruling received in june 2011 from the irs affirmed the tax-free nature of the spin-off . activities related to the downstream business have been treated as discontinued operations in all periods presented in this annual report on form 10-k ( see item 8 . financial statements and supplementary data 2014note 3 to the consolidated financial statements for additional information ) . overview 2013 market conditions exploration and production prevailing prices for the various grades of crude oil and natural gas that we produce significantly impact our revenues and cash flows . prices of crude oil have been volatile in recent years . in 2011 , crude prices increased over 2010 levels , with increases in brent averages outstripping those in wti . during much of 2010 , both wti and brent crude oil monthly average prices remained in the $ 75 to $ 85 per barrel range . crude oil prices reached a low of $ 33.98 in february 2009 , following global demand declines in an economic recession , but recovered quickly ending 2009 at $ 79.36 . the following table lists benchmark crude oil and natural gas price annual averages for the past three years. .
by how much did the brent crude oil benchmark increase from 2010 to 2011?
wti crude oil ( dollars per bbl ) $ 95.11 $ 79.61 $ 62.09 brent ( europe ) crude oil ( dollars per bbl ) 111.26 79.51 61.49 henry hub natural gas ( dollars per mmbtu ) ( a ) $ 4.04 $ 4.39 $ 3.99 ( a ) settlement date average . our u.s . crude oil production was approximately 58 percent sour in 2011 and 68 percent in 2010 . sour crude contains more sulfur than light sweet wti does . sour crude oil also tends to be heavier than light sweet crude oil and sells at a discount to light sweet crude oil because of higher refining costs and lower refined product values . our international crude oil production is relatively sweet and is generally sold in relation to the brent crude benchmark . the differential between wti and brent average prices widened significantly in 2011 to $ 16.15 in comparison to differentials of less than $ 1.00 in 2010 and 2009. .