what should be the code for this question ?
Create a sub-set of the SMB Usage data only with usage variables for July,August,september rather than all the 6 Months using Proc sql ?
Can we see a sample of your data?
Something like this comes to mind:
select * from smbdata
where month(usagedate) in (7, 8, 9);
But there is no way to know for sure.
Your question should describe what SMB Usage data is.