continue to evaluate the nature and extent of these potential impacts to our business, consolidated results of operations, segment results, liquidity and capital resources. Note: Percentage changes may not compute directly as shown due to rounding of amounts presented above. Net sales increased 2.0% in 2020 compared with 2019, reflecting a favorable price realization of 2.3% due to higher prices on certain products and a 0.5% benefit from net acquisitions and divestitures (predominantly driven by the 2019 acquisition of ONE Brands, partially offset by the 2020 divestitures of Krave and the  Scharffen Berger  and  Dagoba  brands). These increases were partially offset by an unfavorable impact from foreign currency exchange rates of 0.5% and a volume decrease of 0.3% due to the impact of COVID-19 on sales in our international markets, as well as declines in owned retail and world travel retail and elasticity-driven impacts due to price increases on certain products. Net sales increased 2.5% in 2019 compared with 2018, reflecting a favorable price realization of 1.7% due to higher prices on certain products, a 1.0% benefit from net acquisitions and divestitures (predominantly driven by the 2019 acquisition of ONE Brands and the 2018 acquisition of Pirate Brands, partially offset by 2018 divestitures) and a volume increase of 0.1%, partially offset by an unfavorable impact from foreign currency exchange rates of 0.3%. Excluding foreign currency, our 2019 net sales increased 2.8%. Consolidated volumes increased due to solid marketplace growth in select international markets. Table of Contents The Hershey Company | 2020 Form 10-K | Page 23 2019 compared with 2018 2020 compared with 2019 Net Sales CONSOLIDATED RESULTS OF OPERATIONS Percent Change For the years ended December 31, 2020 2019 2018 2020 vs 2019 2019 vs 2018 In millions of dollars except per share amounts Net sales $ 8,149.7  $ 7,986.3  $ 7,791.1  2.0  % 2.5  % Cost of sales 4,448.5  4,363.8  4,215.7  1.9  % 3.5  % Gross profit 3,701.2  3,622.5  3,575.4  2.2  % 1.3  % Gross margin 45.4  % 45.4  % 45.9  % SM&A expense 1,890.9  1,905.9  1,874.8  (0.8) % 1.7  % SM&A expense as a percent of net sales 23.2  % 23.9% 24.1% Long-lived and intangible asset impairment charges 9.1  112.5  57.7  (91.9) % 94.9  % Business realignment costs 18.5  8.1  19.1  128.1  % (57.5) % Operating profit 1,782.7  1,596.0  1,623.8  11.7  % (1.7) % Operating profit margin 21.9  % 20.0  % 20.8  % Interest expense, net 149.4  144.1  138.8  3.6  % 3.8  % Other (income) expense, net 138.3  71.1  74.8  94.7  % (5.0) % Provision for income taxes 219.6  234.0  239.0  (6.2) % (2.1) % Effective income tax rate 14.7  % 16.9  % 17.0  % Net income including noncontrolling interest 1,275.4  1,146.8  1,171.2  11.2  % (2.1) % Less: Net loss attributable to noncontrolling interest (3.3) (2.9) (6.5) 12.1  % (54.8) % Net income attributable to The Hershey Company $ 1,278.7 $ 1,149.7 $ 1,177.7 11.2  % (2.4) % Net income per share—diluted $ 6.11 $ 5.46 $ 5.58 11.9  % (2.2) %