Collecting Subscribers of Consecutive Years

Hello Tess Hive Mind, 

I'm looking for a way to pull a list of subscribers that have consecutively subscribed for the last 10+ years that doesn't involve knowledge SQL (i.e. creating a stored procedure/view). I've been playing with Constituencies (and thinking about attributes too...), but we don't want a string of constituencies in the header. For example, I could create a Sub constituency for each fiscal year (S15 for 2014-15, S16 for 2015-16 etc), but the headers would have a ridiculously long list of constituencies. 

Any ideas? 

MB