Same cities over and over again in Global Trade

Much has already been said here about the same items popping up in the Global Trade HQ such as mountain items and wrought iron, but what perplexes me more than anything is the fact that I continually see the same cities there and sometimes they even show up twice in the same refresh. Of all the thousands and maybe even million people playing this game, I don’t understand why I’m seeing the same group over and over again.