I think you got that backwards. Practically all of the Hamburgers in the US are 100% beef, at least 75% of the hotdogs are. Order a hamburger in the UK and you can get pork, soy, egg, bread crumbs, flour, and other assorted crapola. Unless it's specified as a "Beef Burger" get ready for a foul tasting suprise. China has better hamburgers than the UK, I know from extensive experience. ;).
'Practically all of the Hamburgers in the US are 100% beef, at least 75% of the hotdogs are'
100% beef includes organ meat, lips ears, you name it! Same for hotdogs. 100% beef mean 100% from a cow, it doesn't mean prime steak. If I order a burger in the UK it wiil probably be from MuckDonalds or Burger King and will therefore have exactly the same contents as one of your burgers with the exception of the growth hormones US farmers are allowed to feed their cattle and are banned here.