Home Depot Corporation is evaluating upgrading its delivery system for $750,000. The system is expected to generate positive cash flows over the next four years in the amounts of $350,000 in year one, $325,000 in year two, $150,000 in year three, and $180,000 in year four. If Home Depot's cost of capital is 8%, what is the payback period of this project?

fill in blank years. Input your answer as a number rounded to 1 decimal. For example, if the answer is 12.46 years, input your answer as 12.5