On January 1, Enco Co. purchases a milling machine for $15,000. The machine is expected to last seven years and have a salvage value of $1,000. Assuming the company uses the straight-line method, depreciation expense should be $_____ per year.The straight-line method is a time-based depreciation method that is the most popular because it is relatively easy to use. The depreciation expense each year will be the same.