It's only 60 days in a basic store, or is in mine. 

If you keep all the emails from when you list items, or from when they auto relist, you can click on the link for the item for up to 90 days, so that may be a way to access the ones that have dropped off before 60 days, or that you haven't been able to relist within 60 days.  It's a lot of work but you could check the emails against your current and sold listings to see which ones are missing.