Consider the following table for a seven$-$year period:

Year, U$.$S Treasury Bills, Inflation

$1,3\mathrm{.}80\%,-1\mathrm{.}22\%$

$2,3\mathrm{.}65,-2\mathrm{.}36$

$3,4\mathrm{.}55,-1\mathrm{.}26$

$4,4\mathrm{.}97,0\mathrm{.}68$

$5,2\mathrm{.}77,-6\mathrm{.}50$

$6,1\mathrm{.}65,-9\mathrm{.}42$

$7,1\mathrm{.}38,-1\mathrm{.}37$

What was the average real return for Treasury bills for this time period?

Note: Do not round intermediate calculations and enter your answer as a percent rounded to $2$ decimal places, e$.$g$.,3216.$

Average real return: $\_\_\_\_\%$