When archiving done task in org-mode can they still contribute to the overall % completed?

I just started to work with org-mode and I really like it. I've come across this question how to archive the done task in a more automated way. My question is now: Once the done tasks are move to another archive-file do they still contribute to the % completed? Is there a way to make them still contributing to the overall status? Otherwise, as there won't be any done task the completion status will always be 0.