Please answer the given financial question based on the context.
Context: entergy mississippi , inc . management 2019s financial discussion and analysis 2010 compared to 2009 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 ( credits ) . following is an analysis of the change in net revenue comparing 2010 to 2009 . amount ( in millions ) .
||amount ( in millions )|
|2009 net revenue|$ 536.7|
|volume/weather|18.9|
|other|-0.3 ( 0.3 )|
|2010 net revenue|$ 555.3|
the volume/weather variance is primarily due to an increase of 1046 gwh , or 8% ( 8 % ) , in billed electricity usage in all sectors , primarily due to the effect of more favorable weather on the residential sector . gross operating revenues , fuel and purchased power expenses , and other regulatory charges ( credits ) gross operating revenues increased primarily due to an increase of $ 22 million in power management rider revenue as the result of higher rates , the volume/weather variance discussed above , and an increase in grand gulf rider revenue as a result of higher rates and increased usage , offset by a decrease of $ 23.5 million in fuel cost recovery revenues due to lower fuel rates . fuel and purchased power expenses decreased primarily due to a decrease in deferred fuel expense as a result of prior over-collections , offset by an increase in the average market price of purchased power coupled with increased net area demand . other regulatory charges increased primarily due to increased recovery of costs associated with the power management recovery rider . other income statement variances 2011 compared to 2010 other operation and maintenance expenses decreased primarily due to : a $ 5.4 million decrease in compensation and benefits costs primarily resulting from an increase in the accrual for incentive-based compensation in 2010 and a decrease in stock option expense ; and the sale of $ 4.9 million of surplus oil inventory . the decrease was partially offset by an increase of $ 3.9 million in legal expenses due to the deferral in 2010 of certain litigation expenses in accordance with regulatory treatment . taxes other than income taxes increased primarily due to an increase in ad valorem taxes due to a higher 2011 assessment as compared to 2010 , partially offset by higher capitalized property taxes as compared with prior year . depreciation and amortization expenses increased primarily due to an increase in plant in service . interest expense decreased primarily due to a revision caused by ferc 2019s acceptance of a change in the treatment of funds received from independent power producers for transmission interconnection projects. .
Question: what was the percentage change in net revenue in 2011


Answer: The answer is:555.3