Empire Machinery acquired a new machine on January 1, 2006 at a cost of $50,000, which was estimated to have a useful life of 10 years, and a salvage value of $20,000. Straight-line depreciation was used. On January 1, 2012, management decided that the estimate of useful life had been too long and that the machinery would have to be retired after two more years, that is, at the end of the eighth year of service, but would retain its original salvage value. Under this revised estimate, calculate the depreciation expense for the seventh year of use.