Carla Vista Medical manufactures hospital beds and other institutional furniture. The company's comparative balance sheet and income statement for 2019 and 2020 follow. Carla Vista Medical Comparative Balance Sheet As of December 31 2020 2019 Assets Current assets Cash $399,000 $417,400 Accounts receivable, net 1,082,000 776,400 Inventory 738,000 681,000 Other current assets 381,300 247,100 Total current assets 2,600,300 2,121,900 Property, plant, & equipment, net 8,619,960 8,440,065 Total assets $11,220,260 $10,561,965 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 $3,159,000 3,702,700 6,861,700 58,950 104,600 4,195,010 4,358,560 $11,220,260 $2,846,000 3,892,700 6,738,700 58,950 103,850 3,660,465 3,823,265 $10,561,965 Carla Vista 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 5,611,750 5,298,700 Gross profit 4,565,450 4,315,200 Operating expenses 2,840,300 2,634,100 Net operating income 1,725,150 1,681,100 Interest expense 300,300 308,650 Net income before taxes 1,424,850 1,372,450 Income taxes (30%) 427,455 411,735 Net income $997,395 $960,715 Dividends paid Preferred dividends 29,550 29,550 Common dividends 433,350 413,100 Total dividends paid 462,900 442,650 Net income retained 534,545 518,065 Retained earnings, beginning of year 3,660,465 3,142,400 Retained earnings, end of year $4,195,010 $3,660,465 Calculate the following profitability ratios for 2020. (Round answers to 1 decimal place, eg. 50.1%.) % a Gross margin percentage % b. Return on assets % c. Return on common stockholders' equity