Chapin Freight purchased a building for $800,000 and depreciated it on a straight-line basis over a 30-year period. The estimated residual value was $110,000. After using the building for 15 years, Chapin realized that wear and tear on the building would force the company to replace it before 30 years. Starting with the sixteenth year, Chapin began depreciating the building over a revised total life of 20 years and increased the estimated residual value to $170,000. Record depreciation expense on the building for years 15 and 16.