A zero-coupon bond has a par value of $1,000 and a yield-to-maturity of 5%. You purchase the bond when it has exactly 17 years remaining until maturity. You hold the bond for 6 months and then sell it. If the bond's yield-to-maturity is 9% when you sell it, what is your percentage return over this 6-month holding period? When computing bond prices, use a semi-annual compounding period. Enter your answer as a decimal and show 4 decimal places. For example, if your answer is 6.25%, enter .0625.