A firm has outstanding debt with a coupon rate of 10%, nine years maturity, and a price of $1,000 per $1,000 face value. What is the after-tax cost of debt (in percentage) if the marginal tax rate of the firm is 30%?

[Type only the final answer into the response box below (NOT into the Notes box) and in pure numeric format. Do NOT use %/$ signs, commas or spaces (e.g. only enter 10 if it is 10 days/$10/10%)]