$99\, \%$

Evidences for common ancestory of great apes and man are as follows

Evidence from Blood Protein It has been proved by the blood protein tests that man is most closely related to great apes (Chimpanzee and Gorilla) and next closest, in order are the old world monkeys the new world monkeys and tarsiers

Evidence from Blood Group In humans four blood groups $A, B, AB$ and $O$ occurs. The blood groups $A$ and $B$ are found in apes but not in monkeys. This indicates that human beings are more closely related to apes than to monkeys

Evidence from Haemoglobin There is $99\, \%$ homology in haemoglobin of man and gorilla. This suggests that the two are closely related