That's interesting, I never knew the formula was that secret! It wasn't patented at first, hence keeping the ingredients secret, although they can be found in the U.S. Material Safety Data Sheet...although the specific hydrocarbon ratio is not revealed. It can get into the smallest, rusted cracks and crevices thanks to its low viscosity, much less than just about any other lubricating oil or solvent.

WD-40 is amazing, I always carry it and a roll of duct tape in my pickup.