Europe lost in 6 years (1939-1945) almost 50 millions people, but barely felt the pain and rebounded in less than 10 years.
China lost in 4 years, 45 million people to the great famine 1959-1961, but rebounded in less than 10 years.
Russia lost during 5 years 27 million people during the Second World War but was able the rebound in less than 5 years, blowing their first nuclear bomb in 1949.
What about Africa?
Africa lost about 17 millions people to transatlantic slavery (over 3 centuries) and about 2 million to Islamic slave trade, a grand total less than Russia in 5 years, but Africa is still incapable of rebounding from that lost which happened 2 centuries ago.
Africa population is still very skinny and dispersed.
The few area with sizable population are the only only ones which are thriving: Egypt, Nigeria, Ethiopia, …
Population density and economical growth is very much related, and Africa is constantly failing on that ratio.