Suppose that the current one-year rate (one-year spot rate) and expected one-year T-bill rates over the following three years (i.e., years 2, 3, and 4, respectively) are as follows: 1R1=6.80%, E(2r1) =7.30%, E(3r1) =8.30% E(4r1)=8.80%

Using the unbiased expectations theory, what is the current (long-term) rate for four-year-maturity Treasury securities?