O'Brien Ltd.'s outstanding bonds have a $1,000 par value, and they mature in 20 years. Their nominal yield to maturity is 8.50%, they pay interest semiannually, and they sell at a price of $800. What is the bond's nominal (annual) coupon interest rate? Enter your answer rounded to two decimal places. Do not enter % in the answer box. For example, if your answer is 0.12345 or 12.345% then enter as 12.35 in the answer box.