Falcon Corporation purchased a depreciable asset for $840,000 on January 1, 2015. The estimated salvage value is $84,000, and the estimated total useful life is 9 years. The straight-line method is used for depreciation. In 2018, Falcon changed its estimates to a total useful life of 5 years with a salvage value of $140,000. What is 2018 depreciation expense?