Consider the following table for the period from $1973$ through $1980.$

Year T$-$bill return Inflation

$19736\mathrm{.}93\%8\mathrm{.}80\%$

$19748\mathrm{.}0012\mathrm{.}20$

$19755\mathrm{.}807\mathrm{.}01$

$19765\mathrm{.}084\mathrm{.}81$

$19775\mathrm{.}126\mathrm{.}77$

$19787\mathrm{.}189\mathrm{.}03$

$197910\mathrm{.}3813\mathrm{.}31$

$198011\mathrm{.}2412\mathrm{.}40$

Calculate the average return for Treasury bills and the average annual inflation rate $($consumer price index$)$ for this period.

Note: Do not round intermediate calculations and enter your answers as a percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.$

Calculate the standard deviation of Treasury bill returns and inflation over this time period.

Note: Do not round intermediate calculations and enter your answers as a percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.$

Calculate the real return for each year.

Note: A negative answer should be indicated by a minus sign. Do not round intermediate calculations and enter your answers as a percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.$

What is the average real return for Treasury bills?