Your insurance agent is trying to sell you an annuity that costs $$40,000$ today. By buying this annuity, your agent promises that you will receive payments of $$220$ a month for the next $21$ years. What is the rate of return on this investment?

$($Do not round intermediate calculations. Enter your answer as a percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.)$