Does saltwater make metal rust faster than unsalted water?

Salt water does make nails rust faster than non-salted water, because when salt is added to water, it will rust the top layer of the nail, and then make the nail basically shed its top layer. Then the salt will rust that layer, and this process continues until the whole nail is rusted. Normal water can only really rust the top layer, and can't get to the rest of the nail.