From the data shown, determine the ESL of the asset. (Note: Values in the table are AW values, not individual year-end values.)

Years Retained	AW of First Cost, $	AW of Operating Cost, $	AW of Salvage Value, $
1	-158,000	-42,000	99,000
2	-142,000	-30,000	38,095
3	-156,000	-41,000	18,127
4	-170,000	-41,000	6464
5	-164,000	-47,000	3276

The ESL of the asset is year(s).