pre_text: the grand gulf recovery variance is primarily due to increased recovery of higher costs resulting from the grand gulf uprate . the volume/weather variance is primarily due to the effects of more favorable weather on residential sales and an increase in industrial sales primarily due to growth in the refining segment . the fuel recovery variance is primarily due to : 2022 the deferral of increased capacity costs that will be recovered through fuel adjustment clauses ; 2022 the expiration of the evangeline gas contract on january 1 , 2013 ; and 2022 an adjustment to deferred fuel costs recorded in the third quarter 2012 in accordance with a rate order from the puct issued in september 2012 . see note 2 to the financial statements for further discussion of this puct order issued in entergy texas's 2011 rate case . the miso deferral variance is primarily due to the deferral in april 2013 , as approved by the apsc , of costs incurred since march 2010 related to the transition and implementation of joining the miso rto . the decommissioning trusts variance is primarily due to lower regulatory credits resulting from higher realized income on decommissioning trust fund investments . there is no effect on net income as the credits are offset by interest and investment income . entergy wholesale commodities following is an analysis of the change in net revenue comparing 2013 to 2012 . amount ( in millions ) .
post_text: as shown in the table above , net revenue for entergy wholesale commodities decreased by approximately $ 52 million in 2013 primarily due to : 2022 the effect of rising forward power prices on electricity derivative instruments that are not designated as hedges , including additional financial power sales conducted in the fourth quarter 2013 to offset the planned exercise of in-the-money protective call options and to lock in margins . these additional sales did not qualify for hedge accounting treatment , and increases in forward prices after those sales were made accounted for the majority of the negative mark-to-market variance . it is expected that the underlying transactions will result in earnings in first quarter 2014 as these positions settle . see note 16 to the financial statements for discussion of derivative instruments ; 2022 the decrease in net revenue compared to prior year resulting from the exercise of resupply options provided for in purchase power agreements where entergy wholesale commodities may elect to supply power from another source when the plant is not running . amounts related to the exercise of resupply options are included in the gwh billed in the table below ; and entergy corporation and subsidiaries management's financial discussion and analysis .
table: Amount (In Millions)
table: 2012 net revenue $1,854
table: Mark-to-market (58)
table: Nuclear volume (24)
table: Nuclear fuel expenses (20)
table: Nuclear realized price changes 58
table: Other (8)
table: 2013 net revenue $1,802
question: Analyse this data from a financial earnings document. what are the nuclear fuel expenses as a percentage of the decrease in net revenue from 2012 to 2013?