At present. Close off the land route without ensuring that the maritime route is closed, and it will be more than 20 ships per year.
My nephew is a Coastie loadmaster/flight engineer flying interdiction missions on C-130's.
If he's telling you that the Coast Guard is successfully interdicting the existing over-the-beach entries, he's lying to you.
The point being made, poobah is not that the Coasties are intecepting all the illegals arriving by sea, but that I have a pretty good "ear to the ground" on the topic of beach entry. I suspect that you don't. Further, if we didn't have people chaing foot traffic all over 150,000 sq. miles of desert we could utilize those BP people elsewhere.