A financial analyst wanted to determine the mean annual return on mutual funds. In a random sample of $50$ returns she found a mean $12\mathrm{.}9\%.$ If we assume that the population standard deviation is $3\%,$ estimate with $90\%$ confidence the mean annual return on all mutual funds.

What is the average percent return? $($only one decimal place and you do not need to show the percent sign$)$