You buy a 20-year bond with a coupon rate of 8.6% that has a yield to maturity of 9.6%. (Assume a face value of $1,000 and semiannual coupon payments.) Six months later, the yield to maturity is 10.6%. What is your return over the 6 months? (Do not round intermediate calculations. Enter your answer as a percent rounded to 2 decimal places. Negative amount should be indicated by a minus sign.)