Matthias Medical manufactures hospital beds and other institutional furniture. The company's comparative balance sheet and income statement for 2019 and 2020 follow. 2019 Matthias Medical Comparative Balance Sheet As of December 31 2020 Assets Current assets Cash $397,220 Accounts receivable, net 906,800 Inventory 743,000 Other current assets 381,300 Total current assets 2,428,320 Property, plant, & equipment, net 8,678,000 Total assets $11,106,320 $417,400 776,400 681,000 247,000 2,121,800 8,440,100 $10,561,900 Liabilities and Stockholders' Equity Current liabilities Long-term debt Total liabilities Preferred stock, $5 par value Common stock, $0.25 par value Retained earnings Total stockholders' equity Total liabilities and stockholders' equity $2,934,700 3,700,600 6,635,300 58,900 104,600 4,307,520 4,471,020 $11,106,320 $2,846,000 3,892,600 6,738,600 58,900 103,800 3,660,600 3,823,300 $10,561,900 Matthias Medical Comparative Income Statement and Statement of Retained Earnings For the Year 2020 2019 Sales revenue (all on account) $10,177,200 $9,613,900 Cost of goods sold 5,411,800 5,298,700 Gross profit 4,765,400 4,315,200 Operating expenses 2,899,900 2,634,100 Net operating income 1,865,500 1,681,100 Interest expense 300,300 308,600 Net income before taxes 1,565,200 1,372,500 Income taxes (30%) 469,560 411,750 Net income $1,095,640 $960,750 Dividends paid Preferred dividends 29,450 29,450 Common dividends 419,270 413,000 Total dividends paid 448,720 442,450 Net income retained 646,920 518,300 Retained earnings, beginning of year 3,660,600 3,142,300 Retained earnings, end of year $4,307,520 $3,660,600 Calculate the following profitability ratios for 2020. (Round answers to 1 decimal place, e.g. 50.1%.) % a. Gross margin percentage % b. Return on assets % C. Return on common stockholders' equity