On January 1st, 2015, the Mature Nature Incorporated bought a machine which can turn plastic trash into solid degradable bricks. The list price of the machine was $ 100 with the terms of FOB shipping point, 2/5 and n/20 (they paid with cash). FedEx charges $ 10 for this kind of delivery. The salvage value of the equipment was $30, and useful life was 5 years. The installation cost was $ 2 and the cost to repair damage occurred during the installation was $ 2. Routine repair costs were $2 as well. The company uses straight-line depreciation method for this kind of assets. On December 31, 2015, the company recorded depreciation expense.

On December 31, 2016, the company recorded depreciation expense.

On January 1, 2017, the company changed total useful life of the asset to 7 years and the salvage value to $ 8.

Question:

How much is the depreciation expense for 2017?