item 7 . management 2019s discussion and analysis of financial condition and results of operations we are a global integrated energy company with significant operations in the north america , africa and europe . our operations are organized into four reportable segments : 2022 exploration and production ( 201ce&p 201d ) which explores for , produces and markets liquid hydrocarbons and natural gas on a worldwide basis . 2022 oil sands mining ( 201cosm 201d ) 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 2022 integrated gas ( 201cig 201d ) which markets and transports products manufactured from natural gas , such as liquefied natural gas ( 201clng 201d ) and methanol , on a worldwide basis . 2022 refining , marketing & transportation ( 201crm&t 201d ) which refines , markets and transports crude oil and petroleum products , primarily in the midwest , upper great plains , gulf coast and southeastern regions of the united states . 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 the forward-looking statements . we hold a 60 percent interest in equatorial guinea lng holdings limited ( 201cegholdings 201d ) . as discussed in note 4 to the consolidated financial statements , effective may 1 , 2007 , we ceased consolidating egholdings . our investment is accounted for using the equity method of accounting . unless specifically noted , amounts presented for the integrated gas segment for periods prior to may 1 , 2007 , include amounts related to the minority interests . 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 , item 6 . selected financial data and item 8 . financial statements and supplementary data . overview 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 were volatile in 2009 , but not as much as in the previous year . prices in 2009 were also lower than in recent years as illustrated by the annual averages for key benchmark prices below. . 
|Benchmark|2009|2008|2007|
|WTI crude oil (Dollars per barrel)|$62.09|$99.75|$72.41|
|Dated Brent crude oil (Dollars per barrel)|$61.67|$97.26|$72.39|
|Henry Hub natural gas (Dollars per mcf)<sup>(a)</sup>|$3.99|$9.04|$6.86|
 henry hub natural gas ( dollars per mcf ) ( a ) $ 3.99 $ 9.04 $ 6.86 ( a ) first-of-month price index . crude oil prices rose sharply through the first half of 2008 as a result of strong global demand , a declining dollar , ongoing concerns about supplies of crude oil , and geopolitical risk . later in 2008 , crude oil prices sharply declined as the u.s . dollar rebounded and global demand decreased as a result of economic recession . the price decrease continued into 2009 , but reversed after dropping below $ 33.98 in february , ending the year at $ 79.36 . our domestic crude oil production is about 62 percent sour , which means that it 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 dated brent crude benchmark . the differential between wti and dated brent average prices narrowed to $ 0.42 in 2009 compared to $ 2.49 in 2008 and $ 0.02 in 2007. .


Question: by what percentage did the average wti crude oil benchmark decrease from 2007 to 2009? (in percentage)

Solution:
def solution():
    # Define variables name and value
    wti_2009 = 62.09
    wti_2007 = 72.41
    
    # Do math calculation to get the answer
    difference = wti_2009 - wti_2007
    answer = (difference / wti_2007) * 100
    
    return answer

Answer: -14.252175113934532