You Europeans all watch our shows, movies and music way more than you probably listen to the same entertainment that comes from Britian, so I am sure many people pick up the American version more.
Just basing it off my Slovakian girlfriend who says she learned English by watching American television and listening to our music and she also said that American movies and shows were often more popular than native culture. But I don't really know, I speak Afro American which is king of all the English languages.