pre_text: aeronautics business segment 2019s results of operations discussion . the increase in our consolidated net adjustments for 2011 as compared to 2010 primarily was due to an increase in profit booking rate adjustments at our is&gs and aeronautics business segments . aeronautics our aeronautics business segment is engaged in the research , design , development , manufacture , integration , sustainment , support , and upgrade of advanced military aircraft , including combat and air mobility aircraft , unmanned air vehicles , and related technologies . aeronautics 2019 major programs include the f-35 lightning ii joint strike fighter , f-22 raptor , f-16 fighting falcon , c-130 hercules , and the c-5m super galaxy . aeronautics 2019 operating results included the following ( in millions ) : .
post_text: 2012 compared to 2011 aeronautics 2019 net sales for 2012 increased $ 591 million , or 4% ( 4 % ) , compared to 2011 . the increase was attributable to higher net sales of approximately $ 745 million from f-35 lrip contracts principally due to increased production volume ; about $ 285 million from f-16 programs primarily due to higher aircraft deliveries ( 37 f-16 aircraft delivered in 2012 compared to 22 in 2011 ) partially offset by lower volume on sustainment activities due to the completion of modification programs for certain international customers ; and approximately $ 140 million from c-5 programs due to higher aircraft deliveries ( four c-5m aircraft delivered in 2012 compared to two in 2011 ) . partially offsetting the increases were lower net sales of approximately $ 365 million from decreased production volume and lower risk retirements on the f-22 program as final aircraft deliveries were completed in the second quarter of 2012 ; approximately $ 110 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 and to a lesser extent lower volume ; and about $ 95 million from a decrease in volume on other sustainment activities partially offset by various other aeronautics programs due to higher volume . net sales for c-130 programs were comparable to 2011 as a decline in sustainment activities largely was offset by increased aircraft deliveries . 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 lrip 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 . 2011 compared to 2010 aeronautics 2019 net sales for 2011 increased $ 1.3 billion , or 10% ( 10 % ) , compared to 2010 . the growth in net sales primarily was due to higher volume of about $ 850 million for work performed on the f-35 lrip contracts as production increased ; higher volume of about $ 745 million for c-130 programs due to an increase in deliveries ( 33 c-130j aircraft delivered in 2011 compared to 25 during 2010 ) and support activities ; about $ 425 million for f-16 support activities and an increase in aircraft deliveries ( 22 f-16 aircraft delivered in 2011 compared to 20 during 2010 ) ; and approximately $ 90 million for higher volume on c-5 programs ( two c-5m aircraft delivered in 2011 compared to one during 2010 ) . these increases partially were offset by a decline in net sales of approximately $ 675 million due to lower volume on the f-22 program and lower net sales of about $ 155 million for the f-35 development contract as development work decreased. .
table: 2012 2011 2010
table: Net sales $14,953 $14,362 $13,109
table: Operating profit 1,699 1,630 1,498
table: Operating margins 11.4% 11.3% 11.4%
table: Backlog at year-end 30,100 30,500 27,500
question: Analyse this data from a financial earnings document. what was the percent of net sales attributable to the f-35 lrip contracts included in the 2012 sales