A new printing press with an expected ten-year life can be purchased for $117,600 (year 0). The printing press is expected to generate after-tax cash flows of $14,700 per year for each of the first six years of its life (years 1 to 6), and $12,250 per year for each of the remaining four years of its life (years 7 to 10).

What is the payback period in years (round answer up to the first decimal place)?