Over the past five months, Amazon stock returns are $-4\mathrm{.}48\%,-9\mathrm{.}18\%,-8\mathrm{.}29\%,-8\mathrm{.}01\%,$ and $0\mathrm{.}90\%.$ What is the arithmetic average return over the five months $($in $\%)?$

Note:

Express the $\%$ answer in the form of$$ab$.$cd$.$ Keep two $(2)$ numbers after the decimal point.

For example, if your answer is $0\mathrm{.}3245$ or $32\mathrm{.}45\%,$ write $32\mathrm{.}45$ as your answer. Do NOT write $0\mathrm{.}3245.$