Debt with a face value of $59 million and a coupon rate of 4.1% was issued in 2015, when the yield on comparable AAA-rated bonds was 4.1%. Since issuance, the yield to maturity on similar bonds has climbed to 8.0%. If the tax rate is 20%, what is the pre-tax cost of debt? Express your answer as a percent to the nearest decimal place (e.g. 0.0839 should be written as 8.4).