In-House Scrap Rate BAQ

I've been trying to create a BAQ that calculates our in-house scrap rate for a given calendar year. Basically it would be
total amount of rejected DMR's / total amount of all invoices.
I need to be able to use all of the DMR's for the year, not just the ones related to the jobs on the invoices. So far, all I can seem to get are DMR's related to the Invoices.

I was using the InvcHead, InvcDtl, JobProd, and DMRHead tables. Anyone have a clue if these are the correct tables that I should be using?
I've been trying to create a BAQ that calculates our in-house scrap rate for a given calendar year. Basically it would be
total amount of rejected DMR's / total amount of all invoices.
I need to be able to use all of the DMR's for the year, not just the ones related to the jobs on the invoices. So far, all I can seem to get are DMR's related to the Invoices.

I was using the InvcHead, InvcDtl, JobProd, and DMRHead tables. Anyone have a clue if these are the correct tables that I should be using?