Could this be a sampling effect? If you have traction in SFBA then many of the moving searches you see will necessarily be out of SFBA. And conversely: if you

Could this be a sampling effect? If you have traction in SFBA then many of the moving searches you see will necessarily be out of SFBA. And conversely: if you don't have broad coverage, you won't see searches from the hinterlands about moving to large metros.