$20.$ Bond Yields $($LO$2)$ Airbutus Co$.$ wants to issue new $20-$year bonds for some much$-$needed expansion projects. The company currently has $8\%$ coupon bonds on the market that sell for $$930,$ make semiannual payments, and mature in $20$ years. What coupon rate should the company set on its new bonds if it wants them to sell at par?