We have a splicer that appears to be attached to a table with 7500 records. The splicer begins in 2015. user does not know how to change years or add the next year to the splicer. We seem to be out of room.
Firstly, it's called a slicer. Secondly, the slicer will change to reflect the contents of the table on which it is based. Make sure that rows added to the table are indeed a part of the table.
Finally, we can't troubleshoot a picture. Better to attach a sample workbook (desensitised|) that illustrates the problem.
It sounds like the slicer is only connected to the data that goes up to 2015, so it cannot show new years. You need to check the source table and make sure the new years are added there first. Then update the table range or refresh the data so the slicer can see the new rows. If it is a Pivot Table slicer, try refreshing the pivot and check that the date field includes the new years.