{"pre_text": ["entergy new orleans , inc .", "management's financial discussion and analysis net revenue 2008 compared to 2007 net revenue consists of operating revenues net of : 1 ) fuel , fuel-related expenses , and gas purchased for resale , 2 ) purchased power expenses , and 3 ) other regulatory charges .", "following is an analysis of the change in net revenue comparing 2008 to 2007 .", "amount ( in millions ) ."], "post_text": ["the volume/weather variance is due to an increase in electricity usage in the service territory in 2008 compared to the same period in 2007 .", "entergy new orleans estimates that approximately 141000 electric customers and 93000 gas customers have returned since hurricane katrina and are taking service as of december 31 , 2008 , compared to approximately 132000 electric customers and 86000 gas customers as of december 31 , 2007 .", "billed retail electricity usage increased a total of 184 gwh compared to the same period in 2007 , an increase of 4% ( 4 % ) .", "the net gas revenue variance is primarily due to an increase in base rates in march and november 2007 .", "refer to note 2 to the financial statements for a discussion of the base rate increase .", "the rider revenue variance is due primarily to higher total revenue and a storm reserve rider effective march 2007 as a result of the city council's approval of a settlement agreement in october 2006 .", "the approved storm reserve has been set to collect $ 75 million over a ten-year period through the rider and the funds will be held in a restricted escrow account .", "the settlement agreement is discussed in note 2 to the financial statements .", "the base revenue variance is primarily due to a base rate recovery credit , effective january 2008 .", "the base rate credit is discussed in note 2 to the financial statements .", "gross operating revenues and fuel and purchased power expenses gross operating revenues increased primarily due to : an increase of $ 58.9 million in gross wholesale revenue due to increased sales to affiliated customers and an increase in the average price of energy available for resale sales ; an increase of $ 47.7 million in electric fuel cost recovery revenues due to higher fuel rates and increased electricity usage ; and an increase of $ 22 million in gross gas revenues due to higher fuel recovery revenues and increases in gas base rates in march 2007 and november 2007 .", "fuel and purchased power increased primarily due to increases in the average market prices of natural gas and purchased power in addition to an increase in demand. ."], "table": [["", "amount ( in millions )"], ["2007 net revenue", "$ 231.0"], ["volume/weather", "15.5"], ["net gas revenue", "6.6"], ["rider revenue", "3.9"], ["base revenue", "-11.3 ( 11.3 )"], ["other", "7.0"], ["2008 net revenue", "$ 252.7"]], "table_ori": [["", "Amount (In Millions)"], ["2007 net revenue", "$231.0"], ["Volume/weather", "15.5"], ["Net gas revenue", "6.6"], ["Rider revenue", "3.9"], ["Base revenue", "(11.3)"], ["Other", "7.0"], ["2008 net revenue", "$252.7"]]}

Question: what percent of the change between net revenue in 2007 and 2008 was due to rider revenue?
Evidence:
table_1: the 2007 net revenue of amount ( in millions ) is $ 231.0 ;
table_4: the rider revenue of amount ( in millions ) is 3.9 ;
table_7: the 2008 net revenue of amount ( in millions ) is $ 252.7 ;
Program: subtract(252.7, 231.0), divide(3.9, #0)
Answer:
str_answer: 18%
exe_answer: 0.17972