Zachary Co has outstanding bonds with $10$ years remaining until maturity, a coupon rate of $7\%,$ semi$-$annual coupon payments, and a market price of $96\mathrm{.}5\%$ of par value. If the tax rate is $28\%,$ what is the firm's after$-$tax cost of debt? Enter your answer as an annualized rate in decimal format, and show four decimal places. For example, if your answer is $5\mathrm{.}1\%,$ enter $\mathrm{.}0510.$