Nakamichi Bancorp has made an investment in banking software at a cost of $1, 658, 250. Management expects productivity gains and cost savings over the next several years. If, as a result of this investment, the firm is expected to generate additional cash flow of $576, 774, $698, 013, $459, 184, and $335, 620 over the next four years, what is the investment's payback period? (Round answer to 2 decimal places, e.g. 15.25.) Payback period is years