Rhiannon Corporation has bonds on the market with 17.5 years to maturity, a YTM of 6.40 percent, and a current price of $1.037. The bonds make semiannual PAYMENTS. What must the coupon rate be on these bonds? (Do not round intermediate CALCULATIONS and round your final answer to 2 decimal places. (e.g., 32.16)) Coupon rate ___________ %