Create Bandwidth Utilization (bps) Report for NTA IP Address Groups

I have created IP Address Groups in NTA to categorize our web sites by cost centre.  I would like to determine how much of our total bandwidth is used by IP Address Group. 

Currently the NetFlow report can only produce the total ingress and egress bytes instead of Mbps.

Is there a way to generate a NTA IP Address Group report showing bandwidth utilization in bits per second?

I understand this may be achievable by creating a custom SQL report. However, I'm not sure exactly how to do it, ie, do not know the exact SQL query to create.

Thank you.