Fields Company purchased equipment on January 1 for $180,000. This system has a useful life of 8 years and a salvage value of $20,000. The company estimates that the equipment will produce 40,000 units over its 8-year useful life. Actual units produced are: Year 1 - 4,000 units; Year 2 - 6,000 units; Year 3 - 8,000 units; Year 4 - 5,000 units; Year 5 - 4,000 units; Year 6 - 5,000 units; Year 7 - 7,000 units; Year 8 - 3,000 units. What would be the depreciation expense for the second year of its useful life using the straight-line method?