Sesame Company purchased a computer system for $74,000 on January 1, 2011. It was depreciated based on a 7-year life and an $18,000 salvage value using straight line depreciation. On January 1, 2013, Sesame revised these estimates to a total useful life of 4 years and a salvage value of $10,000. Prepare Sesame's entry to record 2013 depreciation expense.