pre_text: item 6 . selected financial data the following table sets forth our selected financial data . the table should be read in conjunction with item 7 and item 8 of this annual report on form 10-k. .
post_text: ( 1 ) long-term debt does not include the current portion of long-term debt , which is included in current liabilities . ( 2 ) free cash flow is a non-gaap financial measure and represents cash from operating activities less capital expenditures net of related grant proceeds . see liquidity and capital resources in item 7 for more information on this measure. .
table: Year Ended December 31
table: ($ in millions, except per share amounts) 2017 2016 2015 2014 2013
table: Sales and service revenues $7,441 $7,068 $7,020 $6,957 $6,820
table: Goodwill impairment — — 75 47 —
table: Operating income (loss) 865 858 769 655 512
table: Net earnings (loss) 479 573 404 338 261
table: Total assets<sup></sup> 6,374 6,352 6,024 6,239 6,190
table: Long-term debt<sup>(1)</sup> 1,279 1,278 1,273 1,562 1,665
table: Total long-term obligations<sup></sup> 3,225 3,356 3,260 3,562 3,277
table: Net cash provided by (used in) operating activities 814 822 861 755 260
table: Free cash flow<sup>(2)</sup> 453 537 673 590 121
table: Dividends declared per share $2.52 $2.10 $1.70 $1.00 $0.50
table: Basic earnings (loss) per share $10.48 $12.24 $8.43 $6.93 $5.25
table: Diluted earnings (loss) per share $10.46 $12.14 $8.36 $6.86 $5.18
question: Analyse this data from a financial earnings document. what was the return on total assets during 2013?