how to find the request per sec by organization ?

Hi I have an event which is comprised of OrgName, RequestName and others. How do i find the the average & max request per sec by OrgName using per_second() function ? I tried doing a timechart of per_sec() by OrgName. But it gives me every second, what is the per_second() with OrgName as the column names. I want to calculate average & max request per sec by OrgName ? Could you please let me know how to achieve this.