Year Ended December 31, 2018(b) 2017(a)(c) 2016(a)(d) 2015(a)(e) 2014(a)(f) (Amounts in thousands, except per share data and ratios) RESULTS OF OPERATIONS Sales $ 3,832,666 $ 3,660,831 $ 3,990,487 $ 4,557,791 $ 4,877,885 Gross profit 1,187,836 1,088,953 1,236,798 1,481,125 1,716,058 Selling, general and administrative expense (943,714) (901,727) (965,376) (970,608) (933,463) Gain (loss) on sale of businesses (7,727 ) 141,317 (7,664 ) — — Operating income 247,538 341,135 276,684 520,377 794,710 Interest expense (58,160 ) (59,730 ) (60,137 ) (65,270 ) (60,322 ) Provision for income taxes(g) (51,224) (258,679) (77,380) (148,351) (209,311) Net earnings attributable to Flowserve Corporation 119,671 2,652 132,455 258,411 513,372 Net earnings per share of Flowserve Corporation common shareholders (basic) 0.91 0.02 1.02 1.94 3.75 Net earnings per share of Flowserve Corporation common shareholders (diluted) 0.91 0.02 1.01 1.93 3.72 Cash flows from operating activities 190,831 311,066 240,476 440,759 594,481 Cash dividends declared per share 0.76 0.76 0.76 0.72 0.64 FINANCIAL CONDITION Working capital $ 1,302,170 $ 1,315,837 $ 1,119,251 $ 1,106,946 $ 1,164,381 Total assets 4,616,277 4,910,474 4,708,923 4,963,106 4,844,667 Total debt 1,483,047 1,575,257 1,570,623 1,620,996 1,145,658 Retirement obligations and other liabilities 459,693 496,954 407,839 387,786 362,970 Total equity 1,660,780 1,670,954 1,637,388 1,664,382 1,930,246 FINANCIAL RATIOS Return on average net assets(h) 5.4 % 0.2 % 5.2 % 9.4 % 17.9 % Net debt to net capital ratio(i) 34.2% 34.3% 42.4% 43.0% 26.4% ITEM 6. SELECTED FINANCIAL DATA 27 (h) Calculated as adjusted net income divided by adjusted net assets, where (i) adjusted net income is the sum of earnings before income taxes, plus interest expense, multiplied by one minus our effective tax rate, and (ii) adjusted net assets is the average of beginning of year and end of year net assets, excluding cash and cash equivalents and debt due in one year. (g) Provision for income taxes in 2017 was impacted by the Tax Reform Act. See Note 16 to our consolidated financial statements included in Item 8 of this Annual Report. (f) Results of operations in 2014 include costs of $10.7 million resulting from realignment initiatives, resulting in a reduction of after tax net earnings of $7.6 million. (e) Results of operations in 2015 include costs of $108.1 million resulting from realignment initiatives, resulting in a reduction of after tax net earnings of $85.0 million. (d) Results of operations in 2016 include costs of $94.8 million resulting from realignment initiatives, resulting in a reduction of after tax net earnings of $75.8 million. (c) Results of operations in 2017 include costs of $71.3 million resulting from realignment initiatives, resulting in a reduction of after tax net earnings of $54.3 million. (b) Results of operations in 2018 include costs of $95.1 million resulting from realignment and transformation initiatives, resulting in a reduction of after tax net earnings of $72.4 million. (a) Retrospective adjustments were made to prior period information to conform to current period presentation. These retrospective adjustments resulted from our adoption ASU No. 2017-07, "Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost," which was effective January 1, 2018. Refer to Note 1 included in this Annual Report for a discussion on the adoption of the standard.