Query Statistics in management data warehouse empty

i am using management data warehouse form SQL Server 2012. I used it before on a 2008 instance a few years ago and everything worked good. However this time i cannot see any Query Stastics data meaning the in built report is empty. The Collector is configured and running. The SQL Server agent Job is collecting and uploading and does not fail. However still i cannot see any queries and there are plenty of them running on that server. Does my service account has no rights? What permissions does it need? I want to mention that for "Server Activity" and "Disk Usage" Report i have no problem and i can see proper values.