Hi @Jennifer_Dungan ,Thanks for the prompt reply!It turned out the extra traffic for the past two years was coming from another server with lots of test accounts. After filtering it out, the data started to look correct and the issue is solved 

I notice a peculiar discrepancy in data when I try to break down the same metric - the number of Unique Visitors - via two different methods:1. Breakdown by User Account Name, an upper table - it gives me somewhat correct data (the numbers match the real number of clients and users that we know from...