As a wild game processor, I can tell you a lot depends on what you as the hunter does. Always make sure you get your animal cooled down fast. Keep the meat as hairless and dirtless as possible. And obviously, the more meat you bring out, the more meat you get back. I think the above estimates are good ideas, but elk can vary alot in size. Also it depends what you have done with your elk. Lots of burger has the highest yield because the meat doesn't have to be as pretty to turn it into hamburger. Steaks take lots of trimming to make sure all the sinew/connective tissue is removed so you take a hit. And smoked products such as jerky and summer sausage give the least yield because you lose all that water weight that cooks off.