A company invests in upgrades to improve the gas mileage of its transportation fleet. These upgrades require an initial investment of $500,000 but save the company $130,000 per year. What is the discounted payback period of these improvements assuming a MARR of 8%, assuming interest is compounded at the end of the year? Click here to access the TVM Factor Table calculator. Carry all interim calculations to 5 decimal places and then round your final answer up to a whole number