Around 6% of males have some form of color blindness. It's not nearly as common in females because the screwed-up genes that lead to colorblindness are almost always recessive and on the X chromosone. Because females have 2 X chromosones, they have a backup if they inherit one bum copy. With 7 billion people on earth, that means at least a quarter of a billion people can't appreciate the same pallet of colors That's almost the entire US population