RJ purchased a tooling machine for $16000 on January 1 of Year 1. The machine was being depreciated using the straight-line method over an estimated useful life of 10 years, with no salvage value. On July 1 of the 6th year, the company estimated that the useful life of the machine would be extended by an additional 4 years beyond its original estimated life and that the salvage value is expected to be $3100. What is the depreciation expense for the above machine for the 6th year?