C'mon man, you know how to do this right, and this isn't it. It's a legitimate question--who built how many tunnels (and when, and how do we know)?

If you know the answer, give it already, and defend your use of "most" instead of trying to get other people to guess what you mean and how you know. If you don't know, walk it back and say "yeah I actually don't know" or "most was an exaggeration" or "I don't think anyone knows for sure now" or whatever it is that is supportable.