You maght have seen items in the catalog or in Workflows that have a status of DISCARD. Twice a year I remove all items that were Withdrawn in the past 6 months, by setting them to DISCARD and then running a report to delete everything marked DISCARD. It takes several days to get through them all, and until all the reports run, items will have the intermediate status of DISCARD. It is more obvious in July than at the beginning of the year, because I can get to doing them earlier, so items may have been Withdrawn as recently as June. At the beginning of the year there are all the annual reports and other housekeeping tasks, so by the time I get to running the maintenance reports it is Feb or March.
If you track how many items your library withdraws in a year, you need to go into REPORTS and get the Count Items-ItemCat1-WD-Prev 6MO:YOURLIBRARY report for items Withdrawn between January 1 and June 30. There is no way to recreate those counts. Please remove your library's copy of the reports when you have safely saved it locally.