Crane Medical manufactures hospital beds and other institutional furniture. The company's comparative balance sheet and income statement for 2019 and 2020 follow. Crane Medical Comparative Balance Sheet As of December 31 2020 2019 Assets Current assets Cash $395,000 $417,450 Accounts receivable, net 1,044,000 776,450 Inventory 717,000 681,100 Other current assets 381,300 247,000 Total current assets 2,537,300 2,122,000 Property, plant, & equipment, net 8,705,975 8,439,980 Total assets $11,243,275 $10,561,980 Liabilities and Stockholders' Equity Current liabilities $3,182,000 $2,846,000 Long-term debt 3,702,600 3,892,650 Total liabilities 6,884,600 6,738,650 Preferred stock, $5 par value 58,950 58,950 Common stock, $0.25 par value 104,650 103,850 Retained earnings 4,195,075 3,660,530 Total stockholders' equity 4,358,675 3,823,330 Total liabilities and stockholders' equity $11,243,275 $10,561,980 Crane Medical Comparative Income Statement and Statement of Retained Earnings For the Year 2020 2019 Sales revenue (all on account) $10,177,250 $9,614,000 Cost of goods sold 5,611,750 5,298,750 Gross profit 4,565,500 4,315,250 Operating expenses 2,840,300 2,634,200 Net operating income 1,725,200 1,681,050 Interest expense 300,350 308,650 Net income before taxes 1,424,850 1,372,400 Income taxes (30%) 427,455 411,720 Net income $997,395 $960,680 Dividends paid Preferred dividends 29,500 29,500 Common dividends 433,400 413,050 Total dividends paid 462,900 442,550 Net income retained 534,545 518,130 Retained earnings, beginning of year 3,660,530 3,142,400 Retained earnings, end of year $4,195,075 $3,660,530 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 %