Mickey and Minnie just bought a zero coupon bond for $$472\mathrm{.}06,$ but they cannot recall when it matures. The yield to maturity equals $13\mathrm{.}0\%.$ Can you help Mickey and Minnie? The bond's face value is $$1000.($Assume annual discounting$)($Enter your answer in years and round to $2$ decimal places.$)$