In Singapore, most people are Rhesus positive (A+, B+, O+, AB+), and less than 1% of the population are Rhesus negative (A–, B–, O– and AB–). 

Rhesus-negative blood is considered rare and precious because patients who have such blood are recommended to receive Rhesus-negative blood. 

Share of the blood donor pool: 

Blood type % of donor pool 
O+ 44.7% 
B+ 24.5% 
A+ 23.9% 
AB+ 5.6% 
O– 0.6% 
A– 0.3% 
B– 0.3% 
AB– 0.1%