The income statements for Arrow Corporation for years ending December 31, 2021 and 2020 follow: + ($ millions) Sales revenue Cost of sales 2021 2020 $150,000 $100,000 100,000 60,000 Selling, general and administrative expenses 35,000 20,000 Depreciation and amortization 3,500 3,000 Earnings before interest expense and income taxes 11,500 17,000 Interest expense 1,500 3,000 Earnings before income taxes 10,000 14,000 Provision for income taxes 2,500 3,500 Net earnings $ 7,500 $ 10,500 a) Prepare common-size income statements for 2021 and 2020. Show four columns of information, one for each year's dollar amounts above, and one next to it for each year showing percentages. Round percentages to two decimal places and format them with a percentage sign. For example, show 2,752/10,000 as 27.52%. b) Comment on the most significant changes. What might these changes mean to an investor?