Add a timestamp to Exchange Rates screen

Description -

Why is this feature important to you - we update exchange rates at the end of each month.  We also have eight business units across the globe who use our instance.  It would be very helpful for them to be able to confirm when rates were last updated.

How would you like the feature to work - Just add a timestamp and maybe the name of the administrator whenever exchange rates are updated.

Current Behaviour - administrator logs into the Exchange Rates tab, updated them, and saves. There is no transaction report or visual indicator (as far as I know) to tell any other users that rates have been updated, or when, or by who.

Thanks!