Refresh updates only

[chrisblank]

I operate a retail drugstore chain and require a category performance report. The trouble is that drilling to down to product level, by categories can leave me with data models containing >9MN rows loaded. The report format does not change monthly, but requires me to refresh the data from the beginning every time I want to update the report. Would it be possible to create a report refresh option that only updates the current data, leaving the previous data in place?

[mdmoo1978]

I would add look for rows that have changed as well, but if it were table/query managed it would even better.