We all know there are 4 types of blood present in human beings in the world. Namely, A, B, O and AB. I want to know what is the most frequent group found in the world population and whch is the least? I would also like to know the percentages of different blood groups in India and the World separately.

That's not a so easy question, I did my best...
http://www.bloodbook.com/world-abo.html

I know the most common is o positive. I am not sure abut the rest