Suppose we observe the three$-$year Treasury security rate $(1$R$3)$ to be $4\mathrm{.}5$ percent, the expected one$-$year rate next year$$E$(2$r$1)$to be $4\mathrm{.}6$ percent, and the expected one$-$year rate the following year$$E$(3$r$1)$to be $4\mathrm{.}7$ percent. If the unbiased expectations theory of the term structure of interest rates holds, what is the one$-$year Treasury security rate? $($Do not round intermediate calculations. Round your percentage answer to $2$ decimal places. $($e$.$g$.,32\mathrm{.}16))$