Unless the gov regs have been changed a lot recently, ice cream needs at least 10 percent butterfat. Anything over that is up to the manufacturer. Store brands typically are as close to the minimum as they can get away with, premium brands around 12 percent and super-premium brands are often in the 16-18 percent butterfat range.
As eatchicago notes, overrun (the percentage volume increase in freezing compared to fluid mix) can go to 100 percent but is rarely much over 50 percent except in the cheapest stuff. There used to be and may still be a separate standard for weight per gallon. This weight standard effectively limits the maximum overrun. It has been around 40 years since I was actively involved with ice cream formulation, but I don't believe that a lot has changed in that time.
Ice cream made with a crank freezer is really tough to get overrun above 40 percent even if you have strong maniacs doing the cranking. Electrically powered freezers, whether put in the freezer compartment or using ice and salt, have not produced as high an overrun as a crank freezer with a fast finish. This is a major part of why homemade ice cream seems to taste creamier even though neither the butterfat nor nonfat milk solids levels usually are even close to the legal standard for ice cream.
For small quantities, usually of sorbets, we like the Salton Minichill. You put the canister in the deep freeze to cool. After putting the canister and stuff in the holder, the handle is turned a few times. This is a great way to make a pint or so with very low overrun.