A company purchased an asset on January 1st 2010 at a cost of $80 000. It is expected to have an estimated salvage value of $10 000 at the end of its 10 year life. After six (6) years of use, the company realized the asset would be useful for only four (4) more years. The company uses the straight line method of depreciation. Calculate the depreciation expense at the end of 2015 and 2016.