Please answer the given financial question based on the context.
Context: the aeronautics segment generally includes fewer programs that have much larger sales and operating results than programs included in the other segments . due to the large number of comparatively smaller programs in the remaining segments , the discussion of the results of operations of those business segments focuses on lines of business within the segment rather than on specific programs . the following tables of financial information and related discussion of the results of operations of our business segments are consistent with the presentation of segment information in note 5 to the financial statements . we have a number of programs that are classified by the u.s . government and cannot be specifically described . the operating results of these classified programs are included in our consolidated and business segment results , and are subjected to the same oversight and internal controls as our other programs . 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 . key combat aircraft programs include the f-35 lightning ii , f-16 fighting falcon , and f-22 raptor fighter aircraft . key air mobility programs include the c-130j super hercules and the c-5m super galaxy . aeronautics provides logistics support , sustainment , and upgrade modification services for its aircraft . aeronautics 2019 operating results included the following : ( in millions ) 2010 2009 2008 .
|( in millions )|2010|2009|2008|
|net sales|$ 13235|$ 12201|$ 11473|
|operating profit|1502|1577|1433|
|operating margin|11.3% ( 11.3 % )|12.9% ( 12.9 % )|12.5% ( 12.5 % )|
|backlog at year-end|27500|26700|27200|
net sales for aeronautics increased by 8% ( 8 % ) in 2010 compared to 2009 . sales increased in all three lines of business during the year . the $ 800 million increase in air mobility primarily was attributable to higher volume on c-130 programs , including deliveries and support activities , as well as higher volume on the c-5 reliability enhancement and re-engining program ( rerp ) . there were 25 c-130j deliveries in 2010 compared to 16 in 2009 . the $ 179 million increase in combat aircraft principally was due to higher volume on f-35 production contracts , which partially was offset by lower volume on the f-35 sdd contract and a decline in volume on f-16 , f-22 and other combat aircraft programs . there were 20 f-16 deliveries in 2010 compared to 31 in 2009 . the $ 55 million increase in other aeronautics programs mainly was due to higher volume on p-3 and advanced development programs , which partially were offset by a decline in volume on sustainment activities . net sales for aeronautics increased by 6% ( 6 % ) in 2009 compared to 2008 . during the year , sales increased in all three lines of business . the increase of $ 296 million in air mobility 2019s sales primarily was attributable to higher volume on the c-130 programs , including deliveries and support activities . there were 16 c-130j deliveries in 2009 and 12 in 2008 . combat aircraft sales increased $ 316 million principally due to higher volume on the f-35 program and increases in f-16 deliveries , which partially were offset by lower volume on f-22 and other combat aircraft programs . there were 31 f-16 deliveries in 2009 compared to 28 in 2008 . the $ 116 million increase in other aeronautics programs mainly was due to higher volume on p-3 programs and advanced development programs , which partially were offset by declines in sustainment activities . operating profit for the segment decreased by 5% ( 5 % ) in 2010 compared to 2009 . a decline in operating profit in combat aircraft partially was offset by increases in other aeronautics programs and air mobility . the $ 149 million decrease in combat aircraft 2019s operating profit primarily was due to lower volume and a decrease in the level of favorable performance adjustments on the f-22 program , the f-35 sdd contract and f-16 and other combat aircraft programs in 2010 . these decreases more than offset increased operating profit resulting from higher volume and improved performance on f-35 production contracts in 2010 . the $ 35 million increase in other aeronautics programs mainly was attributable to higher volume and improved performance on p-3 and advanced development programs as well as an increase in the level of favorable performance adjustments on sustainment activities in 2010 . the $ 19 million increase in air mobility operating profit primarily was due to higher volume and improved performance in 2010 on c-130j support activities , which more than offset a decrease in operating profit due to a lower level of favorable performance adjustments on c-130j deliveries in 2010 . the remaining change in operating profit is attributable to an increase in other income , net between the comparable periods . aeronautics 2019 2010 operating margins have decreased when compared to 2009 . the operating margin decrease reflects the life cycles of our significant programs . specifically , aeronautics is performing more development and initial production work on the f-35 program and is performing less work on more mature programs such as the f-22 and f-16 . development and initial production contracts yield lower profits than mature full rate programs . accordingly , while net sales increased in 2010 relative to 2009 , operating profit decreased and consequently operating margins have declined. .
Question: what is the percentage change in operating income from 2009 to 2010?


Answer: The answer is:-0.04756