You hold an equally$-$weighted $($half invested in each$)$ portfolio consisting of two stocks A and B$,$ whose returns for the past three years are given below.

Year Stock A Stock B

$201822\%-28\%$

$2019-8\%2\%$

$202012\%-18\%$

What are the average return and standard deviation of your portfolio AB$?$ Average return is

$\%,$ standard deviation is

$\%.$ Round your answer to a whole number, e$.$g$.,$ x or xx$.($Hint: Think of portfolio return each year.$)$