One method used to obtain an estimate of the term structure of interest rates is called bootstrapping. Suppose you have a one-year zero coupon bond with a rate of r1 and a two-year bond with an annual coupon payment of C. To bootstrap the two-year rate, you can set up the following equation for the price ( P ) of the coupon bond: p=1+r1c1+(1+r2)2c2+Parvalue Because you can observe all of the variables except r2, the spot rate for two years, you can solve for this interest rate. You find that the one-, two-, three-, and four-year interest rates are 4.2 percent, 4.5 percent, 4.9 percent, and 5.1 percent, respectively. What is the yleld to maturity of a four-year bond with an annual coupon rate of 6.5 percent? (Do not round intermediate calculations. Enter your answer as a percent rounded to 2 decimal places.)