Static Copy of Dynamic Report

I apologize if this has been asked - I searched but everything I saw was asking something slightly different from what I need.

I have a report with yearly targets and actuals. The actuals are updated out of our data warehouse daily; the targets come from an excel doc that is updated manually when targets change (maybe once or twice a month).

I need to be able to view a full report (including filters, drilldowns, etc) as it appeared on Dec 31, every year, for at least a month while the live report populates with a month of the new year's data. All my measures are time indexed, so the "snapshot" report can't be refreshing at all, and can't even "know" that the date isn't Dec 31.

So, basically, every January, I need to have 2 reports, one live and updating, and one a perfect snapshot of the live version, as it was Dec. 31.