Cullumber Bus Lines uses the units-of-activity method in depreciating its buses. One bus was purchased on January 1, 2022, at a cost of $131,000. Over its 4-year useful life, the bus is expected to be driven 236,000 miles. Salvage value is expected to be $7,100. Compute the depreciation cost per unit. (Round answer to 3 decimal places, e.g. 6.251) Depreciation cost per unit $