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.

$\backslash$table$[[$Balance Sheet $($Millions of $$),2021],[$Assets$,$ Cash and securities $$4,200$ Accounts receivable $$17,5000$ Inventories $$20,300$ total current assets. $$42,000$ Net plant and equipment $$28,000$ Total assets $$70,000.$ What is the firm's ROE? Do not round your intermediate calculations.