{"pre_text": ["increased by $ 105.6 million , or 3.4% ( 3.4 % ) , from 2006 to 2007 .", "the following table reflects the components of our revenue growth for the years ended december 31 , 2008 , 2007 and 2006: ."], "post_text": ["( 1 ) core volume growth for the year ended december 31 , 2006 includes .8% ( .8 % ) associated with hauling waste from the city of toronto to one of our landfills in michigan .", "this hauling service is provided to the city at a rate that approximates our cost .", "( 2 ) includes the impact of the acquisition of allied in december 2008 .", "( 3 ) represents new taxes levied on landfill volumes in certain states that are passed on to customers .", "25aa 2008 : during the year ended december 31 , 2008 , our core revenue growth continued to benefit from a broad-based pricing initiative .", "in addition , 14.7% ( 14.7 % ) of our revenue growth is due to our acquisition of allied in december 2008 .", "revenue growth also benefited from higher fuel surcharges and environmental fees .", "however , during 2008 we experienced lower prices for commodities .", "we also experienced a decrease in core volumes primarily due to lower commercial and industrial collection volumes and lower landfill volumes resulting from the slowdown in the economy .", "we expect to continue to experience lower volumes until economic conditions improve .", "25aa 2007 : during the year ended december 31 , 2007 , our revenue growth from core pricing continued to benefit from a broad-based pricing initiative .", "our revenue growth also benefited from higher prices for commodities .", "however , we experienced a decrease in core volume growth primarily due to lower industrial collection and landfill volumes resulting from the slowdown in residential construction .", "25aa 2006 : during the year ended december 31 , 2006 , our revenue growth continued to benefit from our broad-based pricing initiative .", "we experienced core volume growth in our collection and landfill lines of business .", "this core volume growth was partially offset by hurricane clean-up efforts that took place during the fourth quarter of 2005 .", "25aa 2009 outlook : we anticipate internal revenue from core operations to decrease approximately 4.0% ( 4.0 % ) during 2009 .", "this decrease is the expected net of growth in core pricing of approximately 4.0% ( 4.0 % ) and an expected decrease in volume of approximately 8.0% ( 8.0 % ) .", "our projections assume no deterioration or improvement in the overall economy from that experienced during the fourth quarter of 2008 .", "however , our internal growth may remain flat or may decline in 2009 depending on economic conditions and our success in implementing pricing initiatives .", "cost of operations .", "cost of operations was $ 2.4 billion , $ 2.0 billion and $ 1.9 billion , or , as a percentage of revenue , 65.6% ( 65.6 % ) , 63.1% ( 63.1 % ) and 62.7% ( 62.7 % ) , for the years ended december 31 , 2008 , 2007 and 2006 , respectively .", "the increase in cost of operations in aggregate dollars for the year ended december 31 , 2008 versus the comparable 2007 period is primarily a result of our acquisition of allied in december 2008 .", "the remaining increase in cost of operations in aggregate dollars and the increase as a percentage of revenue is primarily due to charges we recorded during 2008 of $ 98.0 million related to estimated costs to comply with f&os issued by the oepa and the aoc issued by the epa in response to environmental conditions at our countywide facility in ohio , $ 21.9 million related to environmental conditions at our closed disposal facility %%transmsg*** transmitting job : p14076 pcn : 048000000 ***%%pcmsg|46 |00044|yes|no|02/28/2009 17:08|0|0|page is valid , no graphics -- color : d| ."], "table": [["", "2008", "2007", "2006"], ["core price", "4.0% ( 4.0 % )", "4.2% ( 4.2 % )", "3.4% ( 3.4 % )"], ["fuel surcharges", "1.8", ".2", "1.1"], ["environmental fees", ".4", ".2", ".4"], ["recycling commodities", ".1", ".9", "-.1 ( .1 )"], ["total price", "6.3", "5.5", "4.8"], ["core volume ( 1 )", "-3.9 ( 3.9 )", "-1.5 ( 1.5 )", "2.4"], ["non-core volume", ".1", "-.1 ( .1 )", "2014"], ["total volume", "-3.8 ( 3.8 )", "-1.6 ( 1.6 )", "2.4"], ["total internal growth", "2.5", "3.9", "7.2"], ["acquisitions net of divestitures ( 2 )", "13.4", "-.5 ( .5 )", "-.1 ( .1 )"], ["taxes ( 3 )", ".1", "2014", ".1"], ["total revenue growth", "16.0% ( 16.0 % )", "3.4% ( 3.4 % )", "7.2% ( 7.2 % )"]], "table_ori": [["", "2008", "2007", "2006"], ["Core price", "4.0%", "4.2%", "3.4%"], ["Fuel surcharges", "1.8", ".2", "1.1"], ["Environmental fees", ".4", ".2", ".4"], ["Recycling commodities", ".1", ".9", "(.1)"], ["Total price", "6.3", "5.5", "4.8"], ["Core volume<sup>(1)</sup>", "(3.9)", "(1.5)", "2.4"], ["Non-core volume", ".1", "(.1)", "—"], ["Total volume", "(3.8)", "(1.6)", "2.4"], ["Total internal growth", "2.5", "3.9", "7.2"], ["Acquisitions, net of divestitures<sup>(2)</sup>", "13.4", "(.5)", "(.1)"], ["Taxes<sup>(3)</sup>", ".1", "—", ".1"], ["Total revenue growth", "16.0%", "3.4%", "7.2%"]]}

Question: what was the average cost of operations from 2006 to 2008 in millions
Evidence:
table_8: the total volume of 2008 is -3.8 ( 3.8 ) ; the total volume of 2007 is -1.6 ( 1.6 ) ; the total volume of 2006 is 2.4 ;
text_23: cost of operations was $ 2.4 billion , $ 2.0 billion and $ 1.9 billion , or , as a percentage of revenue , 65.6% ( 65.6 % ) , 63.1% ( 63.1 % ) and 62.7% ( 62.7 % ) , for the years ended december 31 , 2008 , 2007 and 2006 , respectively .
Program: add(2.4, 2.0), add(#0, 1.9), divide(#1, const_3)
Answer:
str_answer: 2.1
exe_answer: 2.1