How fast does the data change? Would you need to find a realtime source of the latest data to incorporate it into your module? Or would you re-issue the module year by year?
The source that is being used currently is updated at five year intervals (next one is last day of 2019).
I thought about using JSON data, and/or some other mechanism to auto-update, but for now I just put a test in for current localtime year so that if I don't modify anything and I forget when the date hits, CPAN testers will barf an email to me as a reminder :)