2015 compared to 2014 mfc 2019s net sales in 2015 decreased $ 322 million , or 5% ( 5 % ) , compared to the same period in 2014 . the decrease was attributable to lower net sales of approximately $ 345 million for air and missile defense programs due to fewer deliveries ( primarily pac-3 ) and lower volume ( primarily thaad ) ; and approximately $ 85 million for tactical missile programs due to fewer deliveries ( primarily guided multiple launch rocket system ( gmlrs ) ) and joint air-to-surface standoff missile , partially offset by increased deliveries for hellfire . these decreases were partially offset by higher net sales of approximately $ 55 million for energy solutions programs due to increased volume . mfc 2019s operating profit in 2015 decreased $ 62 million , or 5% ( 5 % ) , compared to 2014 . the decrease was attributable to lower operating profit of approximately $ 100 million for fire control programs due primarily to lower risk retirements ( primarily lantirn and sniper ) ; and approximately $ 65 million for tactical missile programs due to lower risk retirements ( primarily hellfire and gmlrs ) and fewer deliveries . these decreases were partially offset by higher operating profit of approximately $ 75 million for air and missile defense programs due to increased risk retirements ( primarily thaad ) . adjustments not related to volume , including net profit booking rate adjustments and other matters , were approximately $ 60 million lower in 2015 compared to 2014 . backlog backlog decreased in 2016 compared to 2015 primarily due to lower orders on pac-3 , hellfire , and jassm . backlog increased in 2015 compared to 2014 primarily due to higher orders on pac-3 , lantirn/sniper and certain tactical missile programs , partially offset by lower orders on thaad . trends we expect mfc 2019s net sales to increase in the mid-single digit percentage range in 2017 as compared to 2016 driven primarily by our air and missile defense programs . operating profit is expected to be flat or increase slightly . accordingly , operating profit margin is expected to decline from 2016 levels as a result of contract mix and fewer risk retirements in 2017 compared to 2016 . rotary and mission systems as previously described , on november 6 , 2015 , we acquired sikorsky and aligned the sikorsky business under our rms business segment . the 2015 results of the acquired sikorsky business have been included in our financial results from the november 6 , 2015 acquisition date through december 31 , 2015 . as a result , our consolidated operating results and rms business segment operating results for the year ended december 31 , 2015 do not reflect a full year of sikorsky operations . our rms business segment provides design , manufacture , service and support for a variety of military and civil helicopters , ship and submarine mission and combat systems ; mission systems and sensors for rotary and fixed-wing aircraft ; sea and land-based missile defense systems ; radar systems ; the littoral combat ship ( lcs ) ; simulation and training services ; and unmanned systems and technologies . in addition , rms supports the needs of government customers in cybersecurity and delivers communication and command and control capabilities through complex mission solutions for defense applications . rms 2019 major programs include black hawk and seahawk helicopters , aegis combat system ( aegis ) , lcs , space fence , advanced hawkeye radar system , tpq-53 radar system , ch-53k development helicopter , and vh-92a helicopter program . rms 2019 operating results included the following ( in millions ) : .

2016: net sales: 13462
operating profit: 906
operating margin: -6.7
backlog atyear-end: 28400
2015: net sales: 9091
operating profit: 844
operating margin: -9.3
backlog atyear-end: 30100
2014: net sales: 8732
operating profit: 936
operating margin: -10.7
backlog atyear-end: 13300

2016 compared to 2015 rms 2019 net sales in 2016 increased $ 4.4 billion , or 48% ( 48 % ) , compared to 2015 . the increase was primarily attributable to higher net sales of approximately $ 4.6 billion from sikorsky , which was acquired on november 6 , 2015 . net sales for 2015 include sikorsky 2019s results subsequent to the acquisition date , net of certain revenue adjustments required to account for the acquisition of this business . this increase was partially offset by lower net sales of approximately $ 70 million for training .

Questions:
what are operating expenses in 2015?
what about in in 2016?
what is the difference in operating expenses from 2015 to 2016?
what percentage change does this represent?

Answers:
8247
12556
4309
52.2%