Alex plans to purchase a callable bond of Horizon Inc. The bond is 20-year to maturity, carry 13.5% annual coupon, paid semi-annually, and have a$1,000 par value. The bond is selling now for $1,287 each. The bond can be called back in 7 years at a call price $1,067.5. What is the yield to call for these bonds? Round the answer to two decimal places in percentage form.