SF - I have less than a 1k records, aggregate on year value filter to return '16, '17, and '18 value

I have less than a thousand records, aggregated based on year values filtered to return '16, '17, and '18 values…but '16 is getting dropped somehow.  Is there a hidden cache I need to clear, or some other setting to get it to pull the full number of records.  been digging and so far no luck.

Do you have a limit on the number of rows returned by the model?  (look in basic tab of model definition for property: “Max # of records (Limit)”)