The Scampini Supplies Company recently purchased a new delivery truck. The new truck costs $25,000, and it is expected to generate after-tax cash flows, including depreciation, of $6,500 per year. The truck has a 5-year expected life. The expected year-end abandonment values (salvage values after tax adjustments) for the truck are given below. The company's WACC is 11%.

Year	Annual After-Tax Cash Flow		Abandonment Value
0	($25,000)			-
1	6,500			$20,000
2	6,500			15,500
3	6,500			13,500
4	6,500			7,500
5	6,500			0

What is the truck's optimal economic life? Round your answer to the nearest whole number.

year(s)