I'm O+ and Bobcat is O-
Bobcat used to get calls all the time from the blood bank because (I guess) O- is in short supply. But, since he was diagnose (and cured) of cancer, he can't donate anymore.
From the American Red Cross:
Almost 40% of the population has O+ blood
Patients with Type O blood must receive Type O blood
About half of all blood ordered by hospitals in our area is Type O
Type O blood is the universal blood type and is the only blood type that can be transfused to patients with other blood types
Only about 7% of all people have Type O negative blood
Type O negative blood is the preferred type for accident victims and babies needing exchange transfusions
There is always a need for Type O donors because their blood may be transfused to a person of any blood type in an emergency