A 5-year zero-coupon bond has a face value of $1,000. If its YTM changes from 3.9% to 4.7%, what is the resulting percentage change in its price? Use the price determined from the first yield, 3.9%, as the base in the percentage calculation. Round to the nearest tenth of a percent. (e.g., 4.321% = 4.3). [Hint: Percent price change = ((P2-P1)/P1)x100. If the price dropped, answer should be negative.]