Suppose you are trying to estimate the after tax cost of debt for a firm as part of the calculation of the Weighted Average Cost of Capital (WACC). The corporate tax rate for this firm is 33%. The firm's bonds pay interest semiannually with a 5.3% coupon rate and have a maturity of 18 years. If the current price of the bonds is $941.93, what is the after tax cost of debt for this firm? (Answer to the nearest tenth of a percent, e.g. 12.3%, but do not use a percent sign).