Board Thread:General Discussion/@comment-24894881-20140503034318/@comment-25926288-20150323171027

What has been seen onscreen, Regina and Cora have a high body count. In total, who knows. We don't see their daily lives in the past so we never will know how many.

Other than that, onscreen (or mentioned) body-count is what I think is the only thing we can use for certaninty.