59  / SERVICE EXCELLENCE Reconciliation of Cash Provided by Operating Activities to Free Cash Foreign Exchange Adjusted % Change FX adjusted % change allows certain financial results to be viewed without the impact of fluctuations in foreign currency exchange rates, thereby facilitating period-to-period comparisons in the analysis of trends in business performance. Financial result variances at constant currency are obtained by translating the comparable period of the prior year results denominated in U.S. dollars at the foreign exchange rates of the current period. FX adjusted % changes in revenues are further used in calculating FX adjusted % change in freight revenue per carload and RTM. These items are presented in Operating Revenues of this Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations. For the year ended December 31 (in millions) 2019 2018 2017 2016 2015 Cash provided by operating activities $ 2,990 $ 2,712 $ 2,182 $ 2,089 $ 2,459 Cash used in investing activities (1,803) (1,458) (1,295) (1,069) (1,123) Effect of foreign currency fluctuations on U.S. dollar-denominated cash and cash equivalents (4 ) 11 (13 ) (13 ) 45 Less: Settlement of forward starting swaps on debt issuance — (24 ) — — — Investment in Central Maine & Québec Railway (174) — — — — Free cash $ 1,357 $ 1,289 $ 874 $ 1,007 $ 1,381 2019 vs. 2018 2018 vs. 2017 (in millions) Reported 2019 Reported 2018 Reported 2017 Variance due to  FX FX Adjusted 2018 FX Adj. % Change Variance due to  FX FX Adjusted 2017 FX Adj. % Change Freight revenues by line of business Grain $ 1,684 $ 1,566 $ 1,532 $ 19 $ 1,585 6 $ — $ 1,532 2 Coal 682 673 631 2 675 1 — 631 7 Potash 462 486 411 6 492 (6) (1) 410 19 Fertilizers and sulphur 250 243 241 4 247 1 (1 ) 240 1 Forest products 304 284 265 5 289 5 (1) 264 8 Energy, chemicals and plastics 1,534 1,243 898 17 1,260 22 (1 ) 897 39 Metals, minerals, and consumer products 752 797 739 16 813 (8) (1) 738 8 Automotive 352 322 293 7 329 7 (2 ) 291 11 Intermodal 1,593 1,538 1,365 10 1,548 3 (1) 1,364 13 Freight revenues 7,613 7,152 6,375 86 7,238 5 (8 ) 6,367 12 Non-freight revenues 179 164 179 1 165 8 — 179 (8) Total revenues $ 7,792 $ 7,316 $ 6,554 $ 87 $ 7,403 5 $ (8 ) $ 6,546 12