a significant portion of our natural gas production in the lower 48 states of the u.s .
is sold at bid-week prices or first-of-month indices relative to our specific producing areas .
average settlement date henry hub natural gas prices have been relatively stable for the periods of this report ; however , a decline began in september 2011 which has continued in 2012 with february averaging $ 2.68 per mmbtu .
should u.s .
natural gas prices remain depressed , an impairment charge related to our natural gas assets may be necessary .
our other major natural gas-producing regions are europe and eg .
natural gas prices in europe have been significantly higher than in the u.s .
in the case of eg our natural gas sales are subject to term contracts , making realized prices less volatile .
the natural gas sales from eg are at fixed prices ; therefore , our worldwide reported average natural gas realized prices may not fully track market price movements .
oil sands mining osm segment revenues correlate with prevailing market prices for the various qualities of synthetic crude oil we produce .
roughly two-thirds of the normal output mix will track movements in wti and one-third will track movements in the canadian heavy sour crude oil marker , primarily western canadian select .
output mix can be impacted by operational problems or planned unit outages at the mines or the upgrader .
the operating cost structure of the oil sands mining operations is predominantly fixed and therefore many of the costs incurred in times of full operation continue during production downtime .
per-unit costs are sensitive to production rates .
key variable costs are natural gas and diesel fuel , which track commodity markets such as the canadian alberta energy company ( 201caeco 201d ) natural gas sales index and crude oil prices , respectively .
recently aeco prices have declined , much as henry hub prices have .
we would expect a significant , continued declined in natural gas prices to have a favorable impact on osm operating costs .
the table below shows average benchmark prices that impact both our revenues and variable costs. .

Benchmark
2011
2010
2009
WTI crude oil<i>(Dollars per bbl)</i>
$95.11
$79.61
$62.09
Western Canadian Select<i>(Dollars per bbl)</i><sup>(a)</sup>
77.97
65.31
52.13
AECO natural gas sales index<i>(Dollars per mmbtu)</i><sup>(b)</sup>
$3.68
$3.89
$3.49

wti crude oil ( dollars per bbl ) $ 95.11 $ 79.61 $ 62.09 western canadian select ( dollars per bbl ) ( a ) 77.97 65.31 52.13 aeco natural gas sales index ( dollars per mmbtu ) ( b ) $ 3.68 $ 3.89 $ 3.49 ( a ) monthly pricing based upon average wti adjusted for differentials unique to western canada .
( b ) monthly average day ahead index .
integrated gas our integrated gas operations include production and marketing of products manufactured from natural gas , such as lng and methanol , in eg .
world lng trade in 2011 has been estimated to be 241 mmt .
long-term , lng continues to be in demand as markets seek the benefits of clean burning natural gas .
market prices for lng are not reported or posted .
in general , lng delivered to the u.s .
is tied to henry hub prices and will track with changes in u.s .
natural gas prices , while lng sold in europe and asia is indexed to crude oil prices and will track the movement of those prices .
we have a 60 percent ownership in an lng production facility in equatorial guinea , which sells lng under a long-term contract at prices tied to henry hub natural gas prices .
gross sales from the plant were 4.1 mmt , 3.7 mmt and 3.9 mmt in 2011 , 2010 and 2009 .
we own a 45 percent interest in a methanol plant located in equatorial guinea through our investment in ampco .
gross sales of methanol from the plant totaled 1039657 , 850605 and 960374 metric tonnes in 2011 , 2010 and 2009 .
methanol demand has a direct impact on ampco 2019s earnings .
because global demand for methanol is rather limited , changes in the supply-demand balance can have a significant impact on sales prices .
world demand for methanol in 2011 has been estimated to be 55.4 mmt .
our plant capacity of 1.1 mmt is about 2 percent of total demand .
operating and financial highlights significant operating and financial highlights during 2011 include : 2022 completed the spin-off of our downstream business on june 30 , 2011 2022 acquired a significant operated position in the eagle ford shale play in south texas 2022 added net proved reserves , for the e&p and osm segments combined , of 307 mmboe , excluding dispositions , for a 212 percent reserve replacement ratio .

Question: Analyse this data from a financial earnings document. how much has the wti crude oil dollars per bbl increased since 2009?
Choices:
0.53181
-0.16041
33.02
50.58032
-0.53181
Correct choice index: 0