2018 2017 2016 2015 2014 Sales $ 81,000 $ 70,000 $ 60,000 $ 57,000 $ 50,000 Cost of goods sold 73,500 45,900 34,200 38,400 30,000 Dollar amounts stated above are in thousands. a. Compute trend percentages for the above items taken from the financial statements of Lopez Plumbing over a five-year period. Treat 2014 as the base year. b. State whether the trends are favorable or unfavorable.