Task: Table-QA (source dataset: FinQA)

Task: 
You are given a table containing structured data and a natural language question referring to the table. Your goal is to analyze the table and provide an accurate and concise answer based on the given data.

Instructions:
1. Understand the Table: Examine the structure, headers, and data in the table. Identify relevant columns and rows related to the question.
2. Interpret the Question: Determine whether the question requires direct retrieval, aggregation, comparison, sorting, filtering, or inference.
3. Extract the Answer: Use logical reasoning and numerical operations (if necessary) to derive the correct response from the table.
4. Format the Answer: No explanation, return the answer in a structured JSON format: {"answer": <answer>}. If the question cannot be answered due to missing or ambiguous data, return a JSON response with {"answer": null}.

Table:
| benchmark                                         | 2013     | 2012     | 2011     |
|:--------------------------------------------------|:---------|:---------|:---------|
| wti crude oil ( dollars per bbl )                 | $ 98.05  | $ 94.15  | $ 95.11  |
| brent ( europe ) crude oil ( dollars per bbl )    | $ 108.64 | $ 111.65 | $ 111.26 |
| henry hub natural gas ( dollars per mmbtu ) ( a ) | $ 3.65   | $ 2.79   | $ 4.04   |

Question:
by what percentage did the average price of wti crude oil increase from 2011 to 2013?


pre_text: item 7 .
management 2019s discussion and analysis of financial condition and results of operations each of our segments is organized and managed based upon both geographic location and the nature of the products and services it offers : 2022 north america e&p 2013 explores for , produces and markets liquid hydrocarbons and natural gas in north america ; 2022 international e&p 2013 explores for , produces and markets liquid hydrocarbons and natural gas outside of north america and produces and markets products manufactured from natural gas , such as lng and methanol , in e.g. ; and 2022 oil sands mining 2013 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 .
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 "anticipates" "believes" "estimates" "expects" "targets" "plans" "projects" "could" "may" "should" "would" or similar words indicating that future outcomes are uncertain .
in accordance with "safe harbor" 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 .
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 stockholders 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 .
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 for all periods prior to the spin-off ( see item 8 .
financial statements and supplementary data 2013 note 3 to the consolidated financial statements for additional information ) .
overview 2013 market conditions prevailing prices for the various qualities of crude oil and natural gas that we produce significantly impact our revenues and cash flows .
the following table lists benchmark crude oil and natural gas price averages relative to our north america e&p and international e&p segments for the past three years. .
post_text: henry hub natural gas ( dollars per mmbtu ) ( a ) $ 3.65 $ 2.79 $ 4.04 ( a ) settlement date average .
north america e&p liquid hydrocarbons 2013 the quality , location and composition of our liquid hydrocarbon production mix can cause our north america e&p price realizations to differ from the wti benchmark .
quality 2013 light sweet crude contains less sulfur and tends to be lighter than sour crude oil so that refining it is less costly and has historically produced higher value products ; therefore , light sweet crude is considered of higher quality and has historically sold at a price that approximates wti or at a premium to wti .
the percentage of our north america e&p crude oil and condensate production that is light sweet crude has been increasing as onshore production from the eagle ford and bakken increases and production from the gulf of mexico declines .
in 2013 , the percentage of our u.s .
crude oil and condensate production that was sweet averaged 76 percent compared to 63 percent and 42 percent in 2012 and 2011 .
location 2013 in recent years , crude oil sold along the u.s .
gulf coast , such as that from the eagle ford , has been priced based on the louisiana light sweet ( "lls" ) benchmark which has historically priced at a premium to wti and has historically tracked closely to brent , while production from inland areas farther from large refineries has been priced lower .
the average annual wti .
label: 0.030910000000000003
qa: answer: 3.1%
ann_table_rows: 1
steps: op: minus2-1
arg1: 98.05
arg2: 95.11
res: 2.94
op: divide2-2
arg1: #0
arg2: 95.11
res: 3.1%
program: subtract(98.05, 95.11), divide(#0, 95.11)
gold_inds: table_1: benchmark the wti crude oil ( dollars per bbl ) of 2013 is $ 98.05 ; the wti crude oil ( dollars per bbl ) of 2012 is $ 94.15 ; the wti crude oil ( dollars per bbl ) of 2011 is $ 95.11 ;
exe_ans: 0.030910000000000003
tfidftopn: text_22: in 2013 , the percentage of our u.s .
text_26: the average annual wti .
program_re: divide(subtract(98.05, 95.11), 95.11)
model_input: text_17
the following table lists benchmark crude oil and natural gas price averages relative to our north america e&p and international e&p segments for the past three years. .
table_1
benchmark the wti crude oil ( dollars per bbl ) of 2013 is $ 98.05 ; the wti crude oil ( dollars per bbl ) of 2012 is $ 94.15 ; the wti crude oil ( dollars per bbl ) of 2011 is $ 95.11 ;
text_20
quality 2013 light sweet crude contains less sulfur and tends to be lighter than sour crude oil so that refining it is less costly and has historically produced higher value products ; therefore , light sweet crude is considered of higher quality and has historically sold at a price that approximates wti or at a premium to wti .