The Maybe Pay Life Insurance Company is trying to sell you an investment policy that will pay you and your heirs $$39,000$ per year

forever. A sales associate for the company told you the policy costs $$640,000.$ At what interest rate would this be a fair deal?

Note: Do not round intermediate calculations and enter your answer as a percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.$