Income statements for Thornton Company for Year 3 and Year 4 follow: THORNTON COMPANY Income Statements Year 4 Year 3 Sales $201,200 $181,200 Cost of goods sold 143,400 121,400 Selling expenses 21,700 19,700 Administrative expenses 12,100 14,100 Interest expense Total expenses Income before taxes Income taxes expense Net income 3,700 5,700 $180,900 $160,900 20,300 6,800 20,300 3,200 $ 13,500 $ 17,100 Required a. Perform a horizontal analysis, showing the percentage change in each income statement component between Year 3 and Year 4. b. Perform a vertical analysis, showing each income statement component as a percentage of sales for each year.