Vertical analysis (common size) percentages for Kochheim Companys sales, cost of goods sold, and expenses are shown below. Vertical Analysis 2015 2014 2013 Sales 100.0 100.0 100.0 Cost of goods sold 46.5 49.9 54.7 Expenses 26.8 25.6 28.2 (a) Calculate net income. 2015 2014 2013 Net income (b) Did Kochheims net income as a percent of sales increase, decrease, or remain unchanged over the 3-year period?