Avamar Sizing

I need a clarification on how to do a correct sizing for Avamar. We are going to order new AVE+DD to replace our existing Avamar system. Let say when I run Capacity report from DPA what I have is 100TB backup protected (before deduplication). Should I sized my new system based on 100TB or based on after deduplication size (which I don't know how to get the exact figure.) Anyone can help?