Pharoah Company purchased a new machine on October 1, 2017, at a cost of $91,360. The company estimated that the machine has a salvage value of $8,000. The machine is expected to be used for 70,200 working hours during its 8-year life. Compute the depreciation expense under the straight-line method for 2017 and 2018, assuming a December 31 year-end.