Machinery purchased for $72,600 by Sheffield Co. in 2013 was originally estimated to have a life of 8 years with a salvage value of $4,840 at the end of that time. Depreciation has been entered for 5 years on this basis. In 2018, it is determined that the total estimated life should be 10 years with a salvage value of $5,445 at the end of that time. Assume straight-line depreciation. Prepare the entry to correct the prior year's depreciation, if necessary.