These rates were once typical in many countries like the UK and US that now have low birth rates. As countries become more well off over time their birth rate drops, so the secret to eradicating overpopulation is eradicating poverty. A low birth rate will then follow, as surely as night follows day.
It is actually expected that the population will continue to grow to around 10 billion after which the population around the globe is expected to drop at a worryingly fast rate. It is already happening in some countries. Japan, Bulgaria and Greece being three examples.
A great quiz in theory, but it becomes too much a matter of clicking around Africa (with a few exceptions), which yes makes a good point. However, data quality for the region is very questionable, e.g. Liberia is included, but not Sierra Leone, nor Guinea.
I think it is more that the elderly die off sooner in these countries leaving behind the younger people. Poverty, disease, lack of medical help, nutrition, smoking etc
Early deaths are definitely a component, but these countries all have very high birth rates. The average woman in Niger has 6.8 children. https://en.wikipedia.org/wiki/List_of_sovereign_states_and_dependencies_by_total_fertility_rate
What makes me think ist that a high birth rate is not the only factor that influences these numbers, but also a shorter lifespan and a higher mortality of children.
Every country here has but a tiny fraction of the per-capita resource consumption of a typical Western one.