Sheffield Company purchased a piece of equipment at the beginning of 2014. The equipment cost $504,000. It has an estimated service life of 8 years and an expected salvage value of $68,040. The sum-of-the-years'-digits method of depreciation is being used. Someone has already correctly prepared a depreciation schedule for this asset. This schedule shows that $84,770 will be depreciated for a particular calendar year. Determine for what particular year the depreciation amount for this asset will be $84,770. Year of depreciation is _________