Hillview Estates purchased a tractor on January 1, 2015, for $65,000. The tractor's useful life is estimated to be 30,000 miles and has a residual value of $5,000. If Hillview used the tractor 5,000 miles in 2015 and 3,000 miles in 2016, what is the balance for accumulated depreciation at the end of 2016 using the units-of-production method?