An investment has an installed cost of $$520,800.$ The cash flows over the four$-$year life of the investment are projected to be $$228,850,$ $$245,450,$ $$212,110,$ and $$160,820,$ respectively.

At what discount rate is the NPV just equal to zero? $($Do not round intermediate calculations and enter your answer as a percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.)$