The balance sheet and income statement shown below are for Koski Inc. Note that the firm has no amortization charges, it does not lease any assets, none of its debt must be retired during the next 5 years, and the notes payable will be rolled over. Balance Sheet (Millions of $) 2021 Assets Cash and securities $ 4,200 Accounts receivable 15,000 Inventories 16,800 Total current assets $ 36,000 Net plant and equipment 24,000 Total assets $ 60,000 Liabilities and Equity Accounts payable $ 18,560 Accruals 10,440 Notes payable 6,000 Total current liabilities $ 35,000 Long-term bonds 10,000 Total liabilities $ 45,000 Common stock 3,750 Retained earnings 11,250 Total common equity $ 15,000 Total liabilities and equity $ 60,000 Income Statement (Millions of $) 2021 Net sales $ 90,000 Operating costs except depreciation 83,700 Depreciation 1,920 Earnings before interest and taxes (EBIT) $ 4,380 Less interest 960 Earnings before taxes (EBT) $ 3,420 Taxes (25%) 855 Net income $ 2,565 Other data: Shares outstanding (millions) 500.00 Common dividends (millions of $) $897.75 Int. rate on notes payable & L-T bonds 6% Federal plus state income tax rate 25% Year-end stock price $61.56 What is the firm's operating margin? Do not round your intermediate calculations.