Sorry I missed your post yesterday. I will have to check my receipt tonight - I am thinking I have had it about 2 years.
If the lens were to need warranty work during the remainder of the coverage period I would be glad to help. Also I think I got this lens locally – If so, there is probably no name on the receipt and the lens has not been registered - in that case the person in possession of both the lens and receipt should have no issues with the warranty.
I will post the purchase date tonight or tomorrow.