Machinery purchased for $50,000 by Tom Brady Co. in 2010 was originally estimated to have a life of 10 years with a salvage value of $5,000 at the end of that time. Depreciation has been entered for 6 years on this basis. In 2016, it is determined that the total estimated life should be 12 years with a salvage value of $2,500 at the end of that time. Assume straight-line depreciation. Determine the depreciation expense for 2016.