Avicorp has a $10.4 million debt issue outstanding, with a 5.8% coupon rate. The debt has semi-annual coupons, the next coupon is due in six months, and the debt matures in five years. It is currently priced at 93% of par value. If Avicorp faces a 25% tax rate, what is its after-tax cost of debt? Express your answer as a percentage with two decimals.