Common-size and trend percentages for a companys net sales, cost of goods sold, and expenses follow: Common-Size Percentages Trend Percentages 2023 2022 2021 2023 2022 2021 Net sales 100.0 % 100.0 % 100.0 % 108.8 % 107.1 % 100.0 % Cost of goods sold 64.8 61.7 58.4 115.6 110.3 100.0 Expenses 13.5 11.9 13.0 109.7 103.7 100.0 Required: a. Calculate the profit percentage for 2021, 2022 and 2023. (Round the final answers to 2 decimal places.) b. Determine whether the companys profit increased, decreased, or remained unchanged during this three-year period