Year Large$-$Company US Treasury Bill

$13\mathrm{.}915\mathrm{.}87$

$214\mathrm{.}352\mathrm{.}51$

$319\mathrm{.}293\mathrm{.}74$

$414\mathrm{.}397\mathrm{.}15$

$531\mathrm{.}885\mathrm{.}34$

$637\mathrm{.}005\mathrm{.}39$

$2.$ Calculate the observed risk premium in each year for the large$-$company stocks versus the T$-$bills. What was the standard deviation of the risk premium over this period? $($Do not round intermediate calculations. Enter your answer as a percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.)$