Year Stock Market Return $(\%)$ T$-$Bill Return $(\%)$

$201631\mathrm{.}800\mathrm{.}03$

$201711\mathrm{.}000\mathrm{.}03$

$20181\mathrm{.}700\mathrm{.}03$

$201913\mathrm{.}100\mathrm{.}21$

$202021\mathrm{.}400\mathrm{.}23$

Required:

What was the risk premium on common stock in each year?

What was the average risk premium?

What was the standard deviation of the risk premium? $($Ignore that the estimation is from a sample of data.$)$