How to determine queries per hour executed by a particular MySQL user?

I am trying to implement user based quota system in MySQL to limit MAX_QUERIES_PER_HOUR for a particular user. I have an option to set this limit via MAX_UPDATES_PER_HOUR 10. But my problem is that I want know that how many queries a user has executed this hour. I followed this thread but this is for global statistics of dba. I want this information for every user of my database. I am sure that MySQL is storing this schema somewhere but after a lot of scrutinizing some of databases like information_schema , performance_schema , mysql I can't figure out how it will be achieved.