A company is raising money by selling bonds. The bonds are offered at a discount at $$800.$ The face value of the bond is $$1000$ with a $20$ year maturity $($meaning in $20$ years you can cash in the bond at face value$).$ The bond pays a dividend annually at a $4\%$ annual return rate $($$$40$ per each dividend payment$).$ Considering all this what is the effective annual interest rate? $($to the nearest $0\mathrm{.}01\%)$