Determine daily change rate

Hey All, 

I would like to know how you guys determine your daily change rate in NetBackup. Although this might seem like a pretty straight forward question, I'm having trouble determining this in a deduplicated environment. Do I compare my daily backup size with the output from nbdeployutil ?

Seeing nbdeployutil should tell me my FETB size, can I assume that I need to compare my incr size to that output ? When compairing incr backup size with full backup size I get weird numbers. 

Note that I'm trying to determin a global daily change % for my entire environment on a per policy type. I'm not looking to get this per machine as my environment is to big.

Any inputs or ideas are highly appreciated.

 

Kind regards

 

Gert