McConnell Corporation has bonds on the market with 17.5 years to maturity, a YTM of 6.4 percent, a par value of $1,000, 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 enter your answer as a percent rounded to 2 decimal places, e.g., 32.16.) Coupon rate