aeronautics 2019 operating profit for 2012 increased $ 69 million , or 4% ( 4 % ) , compared to 2011 . the increase was attributable to higher operating profit of approximately $ 105 million from c-130 programs due to an increase in risk retirements ; about $ 50 million from f-16 programs due to higher aircraft deliveries partially offset by a decline in risk retirements ; approximately $ 50 million from f-35 production contracts due to increased production volume and risk retirements ; and about $ 50 million from the completion of purchased intangible asset amortization on certain f-16 contracts . partially offsetting the increases was lower operating profit of about $ 90 million from the f-35 development contract primarily due to the inception-to-date effect of reducing the profit booking rate in the second quarter of 2012 ; approximately $ 50 million from decreased production volume and risk retirements on the f-22 program partially offset by a resolution of a contractual matter in the second quarter of 2012 ; and approximately $ 45 million primarily due to a decrease in risk retirements on other sustainment activities partially offset by various other aeronautics programs due to increased risk retirements and volume . operating profit for c-5 programs was comparable to 2011 . adjustments not related to volume , including net profit booking rate adjustments and other matters described above , were approximately $ 30 million lower for 2012 compared to 2011 . backlog backlog decreased in 2013 compared to 2012 mainly due to lower orders on f-16 , c-5 , and c-130 programs , partially offset by higher orders on the f-35 program . backlog decreased in 2012 compared to 2011 mainly due to lower orders on f-35 and c-130 programs , partially offset by higher orders on f-16 programs . trends we expect aeronautics 2019 net sales to increase in 2014 in the mid-single digit percentage range as compared to 2013 primarily due to an increase in net sales from f-35 production contracts . operating profit is expected to increase slightly from 2013 , resulting in a slight decrease in operating margins between the years due to program mix . information systems & global solutions our is&gs business segment provides advanced technology systems and expertise , integrated information technology solutions , and management services across a broad spectrum of applications for civil , defense , intelligence , and other government customers . is&gs has a portfolio of many smaller contracts as compared to our other business segments . is&gs has been impacted by the continued downturn in federal information technology budgets . is&gs 2019 operating results included the following ( in millions ) : .

Table: 2013 2012 2011 net sales $ 8367 $ 8846 $ 9381 operating profit 759 808 874 operating margins 9.1% ( 9.1 % ) 9.1% ( 9.1 % ) 9.3% ( 9.3 % ) backlog at year-end 8300 8700 9300

2013 compared to 2012 is&gs 2019 net sales decreased $ 479 million , or 5% ( 5 % ) , for 2013 compared to 2012 . the decrease was attributable to lower net sales of about $ 495 million due to decreased volume on various programs ( command and control programs for classified customers , ngi , and eram programs ) ; and approximately $ 320 million due to the completion of certain programs ( such as total information processing support services , the transportation worker identification credential ( twic ) , and odin ) . the decrease was partially offset by higher net sales of about $ 340 million due to the start-up of certain programs ( such as the disa gsm-o and the national science foundation antarctic support ) . is&gs 2019 operating profit decreased $ 49 million , or 6% ( 6 % ) , for 2013 compared to 2012 . the decrease was primarily attributable to lower operating profit of about $ 55 million due to certain programs nearing the end of their lifecycles , partially offset by higher operating profit of approximately $ 15 million due to the start-up of certain programs . adjustments not related to volume , including net profit booking rate adjustments and other matters , were comparable for 2013 compared to 2012 compared to 2011 is&gs 2019 net sales for 2012 decreased $ 535 million , or 6% ( 6 % ) , compared to 2011 . the decrease was attributable to lower net sales of approximately $ 485 million due to the substantial completion of various programs during 2011 ( primarily jtrs ; odin ; and u.k . census ) ; and about $ 255 million due to lower volume on numerous other programs ( primarily hanford; .

Question: as part of the is&gs results of operation what as the average operating profit from 2011 to 2013
Answer: 813.6
Calculation: divide(add(add(759, 808), 874), const_3)