Sharepoint Dedup rate

Hi,

I'm starting to use deduplication in Netbackup and I was wondering if somebody could tell me what the average dedup rate for sharepoint backups is?

I'm doing a backup of a Sharepoint 2007 environment and I get a dedup rate of 8%. Is this normal?
The environment consists of a sharepoint server and a seperated SQL server.

Regards,
Erwin