An investor purchases a 13-year, 8.7% annual coupon payment bond at a price equal to par value. after the bond is purchased and before the first coupon is recieved, interest rates increase by 1.8%. the investor sells the bond after 3 years. Assume that interest rates remain unchanged at 8.7%+1.8% over the 3-year holding period. Assuming that all coupons are reinvested over the holding period, what is the investor's 3-year horizon yield?