AB⁻ is the rarest blood group in general, in the world population.
O+ , A+ , B+ , AB+ is the order of rarity in general. But the numbers can vary a little bit between B+ and AB+...
O- , A- , B- and AB- are rare in general.
B- and AB- are quite less as compared to others. But their percentages are very close too.
O+ is most common.