Report to show prior periods opened?

I'll take anything I can get, so either a report to show when all historical periods were last unlocked or uncertified.  We had everything certified and locked, and it was unlocked, uncertified, and then data was loaded, certified, and locked.  This was all done without us knowing and we just happened to stumble on it during the following month end. 

We can get the dates it happened by using the "audit workflow" option, but that's only an option if we know a period has been unlocked/uncertified.  We need a report to detect that something has happened after we have certified and locked.