You could try something like this:
select * from V_QOS_INTERFACE_UTILIZATION
where sampletime > '2016-06-01 00:00:00.000'
and sampletime < '2016-07-31 23:59:59.999'
That should give you a starting point. I pulling the data from a view (there is a script in the forums to create them) which makes my query alot easier since I do not have to find the RN table.