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 % 106.8 % 105.6 % 100.0 % Cost of goods sold 52.7 49.7 46.4 116.0 110.7 100.0 Expenses 22.9 19.1 21.3 112.5 105.0 100.0 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