These are the most important subgroups in the system. A1 equals approximately 80% of
the entire A blood type population, and A2 makes up the remaining 20%, under current data.
This means that all other subgroups must be rare. These figures show that A1’s equal 32% of
the entire population in the U.S., while A2’s make up a full 8% of the population, or an amount
double that of the entire AB population and nearly as large a group as all the B’s in the U.S. One
out of every 5 A’s is an A2.