A company reports sales of $$5,000,000,$ net income of $$800,000,$ total assets of $$2,000,000,$ taxes $$30,000,$ interests $$43,200,$ and operation expense $$670,000.$ What is the firm's gross profit margin?

$30\mathrm{.}86\%$

$17\mathrm{.}46\%$

$30\mathrm{.}26\%$

$29\mathrm{.}40\%$