The following details are provided by a manufacturing company: Product line Investment $1,000,000 Useful life 14 years Estimated annual net cash inflows for first year $400,000 Estimated annual net cash inflows for second year $380,000 Estimated annual net cash inflows for next ten years $310,000 Residual value $90,000 Depreciation method Straight - line Required rate of return 12% Calculate the payback period for the investment. (Round your answer to two decimal places.)