bhge 2018 form 10-k | 31 business environment the following discussion and analysis summarizes the significant factors affecting our results of operations , financial condition and liquidity position as of and for the year ended december 31 , 2018 , 2017 and 2016 , and should be read in conjunction with the consolidated and combined financial statements and related notes of the company .we operate in more than 120 countries helping customers find , evaluate , drill , produce , transport and process hydrocarbon resources .our revenue is predominately generated from the sale of products and services to major , national , and independent oil and natural gas companies worldwide , and is dependent on spending by our customers for oil and natural gas exploration , field development and production .this spending is driven by a number of factors , including our customers' forecasts of future energy demand and supply , their access to resources to develop and produce oil and natural gas , their ability to fund their capital programs , the impact of new government regulations and most importantly , their expectations for oil and natural gas prices as a key driver of their cash flows .oil and natural gas prices oil and natural gas prices are summarized in the table below as averages of the daily closing prices during each of the periods indicated. .
[['', '2018', '2017', '2016'], ['brent oil prices ( $ /bbl ) ( 1 )', '$ 71.34', '$ 54.12', '$ 43.64'], ['wti oil prices ( $ /bbl ) ( 2 )', '65.23', '50.80', '43.29'], ['natural gas prices ( $ /mmbtu ) ( 3 )', '3.15', '2.99', '2.52']]
brent oil prices ( $ /bbl ) ( 1 ) $ 71.34 $ 54.12 $ 43.64 wti oil prices ( $ /bbl ) ( 2 ) 65.23 50.80 43.29 natural gas prices ( $ /mmbtu ) ( 3 ) 3.15 2.99 2.52 ( 1 ) energy information administration ( eia ) europe brent spot price per barrel ( 2 ) eia cushing , ok wti ( west texas intermediate ) spot price ( 3 ) eia henry hub natural gas spot price per million british thermal unit 2018 demonstrated the volatility of the oil and gas market .through the first three quarters of 2018 , we experienced stability in the north american and international markets .however , in the fourth quarter of 2018 commodity prices dropped nearly 40% ( 40 % ) resulting in increased customer uncertainty .from an offshore standpoint , through most of 2018 , we saw multiple large offshore projects reach positive final investment decisions , and the lng market and outlook improved throughout 2018 , driven by increased demand globally .in 2018 , the first large north american lng positive final investment decision was reached .outside of north america , customer spending is highly driven by brent oil prices , which increased on average throughout the year .average brent oil prices increased to $ 71.34/bbl in 2018 from $ 54.12/bbl in 2017 , and ranged from a low of $ 50.57/bbl in december 2018 , to a high of $ 86.07/bbl in october 2018 .for the first three quarters of 2018 , brent oil prices increased sequentially .however , in the fourth quarter , brent oil prices declined 39% ( 39 % ) versus the end of the third quarter , as a result of increased supply from the u.s. , worries of a global economic slowdown , and lower than expected production cuts .in north america , customer spending is highly driven by wti oil prices , which similar to brent oil prices , on average increased throughout the year .average wti oil prices increased to $ 65.23/bbl in 2018 from $ 50.80/bbl in 2017 , and ranged from a low of $ 44.48/bbl in december 2018 , to a high of $ 77.41/bbl in june 2018 .in north america , natural gas prices , as measured by the henry hub natural gas spot price , averaged $ 3.15/ mmbtu in 2018 , representing a 6% ( 6 % ) increase over the prior year .throughout the year , henry hub natural gas spot prices ranged from a high of $ 6.24/mmbtu in january 2018 to a low of $ 2.49/mmbtu in february 2018 .according to the u.s .department of energy ( doe ) , working natural gas in storage at the end of 2018 was 2705 billion cubic feet ( bcf ) , which was 15.6% ( 15.6 % ) , or 421 bcf , below the corresponding week in 2017. .

Question: what is the average percent change in natural gas prices?
Answer: 12.1%