AB negative is the rarest in population
.08% I believe
Most people have Rh positive...and that means simian DNA
Negative Rhesus factor is more rare throughout the population
Most lost their babies when more blood types chose to mix-until 'science' worked an angle and then introduced the Gamma Globulin shots to suppress the mothers immune system...now more risk it as there is a constrainer they can use
Negative bloodtypes are much rarer than the Positives/
Other rare blood types, even more uncommon but rarely required
There are exotic blood types in other classifications: "The rarest blood type found is called bombay blood (subtype h-h), found only in a Czechoslovakian nurse in 1961 and in a brother and sister in Massachusetts in 1968."
"Bombay blood (hh) is the rarest of the rare blood types, essentially being completely outside the ABO system that the rest of humanity has. They do not have the A or B antigens, and instead of having the H antigen which defines type O, they actually produce antibodies to H.
This blood type was first discovered in Bombay in 1950 and that is where the name comes from. People who have this type of blood can only receive blood from others with the same type of blood, and there are very few of them. One article about a boy in India with this blood type states that there are only 57 people in India with Bombay blood."
[link to everything2.com