Answer: The approximate distribution of blood types in the U.S. population is as follows: 1  O-positive: 38 percent. 2  O-negative: 7 percent. 3  A-positive: 34 percent. 4  A-negative: 6 percent. 5  B-positive: 9 percent. 6  B-negative: 2 percent. 7  AB-positive: 3 percent.