I've always wondered what the milk fat content of Half and Half is. It's half milk, half cream. But milk can be anywhere from 0% to 4%, and cream can be anywhere from 18% to 36% depending on if you are getting a lighter table cream or a heavier whipping cream. It's a real math problem.
This chart at wikipedia answers this and more.
Half and half is 10% to 18% milk fat. Seems kind of loose to me. If you have a name for something, it should have a specific fat content. Skim milk is always 0%. Whole milk is always 4%. Why can't Half and Half always be say, 14%?
If I ran a dairy, I'd put the fat content in a big font on the label regardless of what was being produced. Butter would have a 100%, skim milk a 0%, and everything in between would be clearly labeled as well.