A machine costing $900,000 with a 4-year life and an estimated salvage value of $60,000 is installed by Peters Company on January 1. The company estimates the machine will produce 2,100,000 units of product during its life. It actually produces the following units for the first 2 years: Year 1 - 500,000; Year 2-500,000; Year 3 - 500,000; Year 4 - 630,000. the Units of Production depreciation method. . Calculate the depreciation expense per unit