White infant mortality in 1915 was almost 100 deaths per 1000 births, and black infant mortality was fully 180 deaths per 1000 births. Both are horrifying. Nowadays white infant mortality is about nine per thousand, and black infant mortality is about 18 per thousand. Of course it is bad that mortality for blacks is higher than for whites. Yet the public has the impression that we should be mainly distressed about the state of black infant mortality.
Population grows at various rates under various conditions.
Sometimes population size shrinks for centuries due to poor political and health conditions. That is, economic, cultural, and political events, and not just catastrophe, control population size. But recently conditions have improved dramatically and population has added another growth spurt - joyous news for humanity.