Thanks for doing this work. I think either I misunderstand the way the calculation works, or the data needs to be filtered by time a bit. If you take the data for the last 60 days and run your calculation, you will find the retention rate to be 100%, since every account votes at least once, and no account therefore will not have voted in the last 60 days. I reckon you need to exclude the last 60 days of new accounts from the calculation in order to prevent the data from being skewed. Or do I misunderstand?