Do you know blood types? Special care must be taken in selecting new blood for a badly injured person, who would be killed by the transfusion   if the blood is too different from his own. There are four basic types of blood A. B. A B. and O. Blood type, like hair and height, comes from parents. Basically, A and B can not be mixed. AB, sometimes called the universal recipient  , may receive A or B,. O type, often called the universal donor  , gives his blood to any other group. Patients usually receive nothing, but salt or plasma   until their blood can be matched as exactly as possible in the blood bank of a hospital. There is a relationship between your blood type and your nationality  . Among Europeans, about 42 % have type A while 45 % have type O. The fewest is the type B. From this passage we can know that among Europeans   _   13 % have the type B.
about no more than less than at most