Typically most developing countries have a population structure shape that can generally be described as a вЂњpyramidвЂќ, a broad base that tapers off steadily with increasing age.
Figure 6: Projection Population Structure With & Without the AIDS Epidemic, Botswana, 2020
(Source: UNAIDS, June 2000).
As the HIV/AIDS epidemic begins to take its toll, the pyramid shape is being replaced by a вЂњchimneyвЂќ shape. The pyramid base becomes narrower, the female population above the age of 20 and the male population above the age of 30 shrinks radically. The exact implications of this new population structure are not clear (US Bureau of the Census, 2001; UNAIDS, 2000).