According to the United Nations, the population of Sub-Saharan Africa is growing more than 3 times faster than the global average at 2.5%. This is largely due to a slower decline in the fertility rate in Sub-Saharan Africa compared to the rest of the world. Globally, the fertility rate has dropped from 4.9 births per women in 1950 to 2.4 in 2020, while in Sub-Saharan Africa it has dropped from 6.5 to 4.7.

Sources: one, two, three, four