Accumulated Depreciation Oregon Steel Mills reported the following items on its December 31, 2003 balance sheet ($ in thousands): Property, plant, and equipment, net $477,581 Accumulated depreciation 440,607 1. Compute Oregon Steel's historical cost of property, plant, and equipment on December 31, 2003. 2. If Oregon Steel uses an 18-year economic life for computing straight-line depreciation on most of its assets, are most of their assets more than or less than 9 years old? Explain how you can determine this.