Chamberlain Co. wants to issue new 15-year bonds for some much-needed expansion projects. The company currently has 8.6 percent coupon bonds on the market that sell for $878.41, make semiannual payments, and mature in 15 years. What coupon rate should the company set on its new bonds if it wants them to sell at par? Assume a par value of $1,000. Do not use excel code.