operating profit for the segment increased by 15% ( 15 % ) in 2005 compared to 2004 . operating profit increased by $ 80 million at m&fc mainly due to improved performance on fire control and air defense programs . performance on surface systems programs contributed to an increase in operating profit of $ 50 million at ms2 . pt&ts operating profit increased $ 10 million primarily due to improved performance on simulation and training programs . the increase in backlog during 2006 over 2005 resulted primarily from increased orders on certain platform integration programs in pt&ts . space systems space systems 2019 operating results included the following : ( in millions ) 2006 2005 2004 .
what were average net sales for space systems from 2004 to 2006 , in millions?
net sales for space systems increased by 16% ( 16 % ) in 2006 compared to 2005 . during the year , sales growth in satellites and strategic & defensive missile systems ( s&dms ) offset declines in space transportation . the $ 1.1 billion growth in satellites sales was mainly due to higher volume on both government and commercial satellite programs . there were five commercial satellite deliveries in 2006 compared to no deliveries in 2005 . higher volume in both fleet ballistic missile and missile defense programs accounted for the $ 114 million sales increase at s&dms . in space transportation , sales declined $ 102 million primarily due to lower volume in government space transportation activities on the titan and external tank programs . increased sales on the atlas evolved expendable launch vehicle launch capabilities ( elc ) contract partially offset the lower government space transportation sales . net sales for space systems increased by 7% ( 7 % ) in 2005 compared to 2004 . during the year , sales growth in satellites and s&dms offset declines in space transportation . the $ 410 million increase in satellites sales was due to higher volume on government satellite programs that more than offset declines in commercial satellite activities . there were no commercial satellite deliveries in 2005 , compared to four in 2004 . increased sales of $ 235 million in s&dms were attributable to the fleet ballistic missile and missile defense programs . the $ 180 million decrease in space transportation 2019s sales was mainly due to having three atlas launches in 2005 compared to six in 2004 . operating profit for the segment increased 22% ( 22 % ) in 2006 compared to 2005 . operating profit increased in satellites , space transportation and s&dms . the $ 72 million growth in satellites operating profit was primarily driven by the volume and performance on government satellite programs and commercial satellite deliveries . in space transportation , the $ 39 million growth in operating profit was attributable to improved performance on the atlas program resulting from risk reduction activities , including the first quarter definitization of the elc contract . in s&dms , the $ 26 million increase in operating profit was due to higher volume and improved performance on both the fleet ballistic missile and missile defense programs . operating profit for the segment increased 25% ( 25 % ) in 2005 compared to 2004 . operating profit increased in space transportation , s&dms and satellites . in space transportation , the $ 60 million increase in operating profit was primarily attributable to improved performance on the atlas vehicle program . satellites 2019 operating profit increased $ 35 million due to the higher volume and improved performance on government satellite programs , which more than offset the decreased operating profit due to the decline in commercial satellite deliveries . the $ 20 million increase in s&dms was attributable to higher volume on fleet ballistic missile and missile defense programs . in december 2006 , we completed a transaction with boeing to form ula , a joint venture which combines the production , engineering , test and launch operations associated with u.s . government launches of our atlas launch vehicles and boeing 2019s delta launch vehicles ( see related discussion on our 201cspace business 201d under 201cindustry considerations 201d ) . we are accounting for our investment in ula under the equity method of accounting . as a result , our share of the net earnings or losses of ula are included in other income and expenses , and we will no longer recognize sales related to launch vehicle services provided to the u.s . government . in 2006 , we recorded sales to the u.s . government for atlas launch services totaling approximately $ 600 million . we have retained the right to market commercial atlas launch services . we contributed assets to ula , and ula assumed liabilities related to our atlas business in exchange for our 50% ( 50 % ) ownership interest . the net book value of the assets contributed and liabilities assumed was approximately $ 200 million at .