Please answer the given financial question based on the context.
Context: 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 ) .
||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|
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. .
Question: what percent of the change between net revenue in 2007 and 2008 was due to rider revenue?


Answer: The answer is:0.17972