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 .
[['( in millions )', '2006', '2005', '2004'], ['net sales', '$ 7923', '$ 6820', '$ 6359'], ['operating profit', '746', '609', '489'], ['backlog at year-end', '18768', '15925', '16112']]
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 .

Question: what were average operating profitfor space systems from 2004 to 2006 , in millions?
Answer: 615