Due to business expansion, a company purchased a $35,000 new engine to renovate its delivery van. The company paid $5,000 for installation and $1,000 interest to finance the purchase. The company believes the estimated useful life of the van can be extended for 3 more years with no residual value. At the date of installation, the net book value of the van is $12,000. The original estimated useful life is 5 years and the van has been used for 4 years. Required: Calculate the annual depreciation of the van after renovation