An investment project costs $13,600 and has annual cash flows of $3,100 for 6 years. If the discount rate is zero percent, the discounted payback period is ______years. If the discount rate is 5 percent, the discounted payback period is ______ years. If the discount rate is 20 percent, the discounted payback period is _________years. (Enter 0 when there is no payback period. Round your answers to 2 decimal places. (e.g., 32.16))