Ashes Divide Corporation has bonds on the market with 18 years to maturity, a YTM of 6.4 percent (APR), and a current price of $1,256.50. The bonds make semiannual payments. What must the coupon rate be on these bonds (as an APR)? Note: first find the semi-annual payment. Then convert it into an annual payment and use this annual payment to find the coupon rate as an APR.