AIDS Statistics and Changing Definition.
The definition of AIDS has been changed several times, most recently (1993) to include people with a positive HIV test but who were not sick. As a result, declining AIDS statistics under the old definition were turned into a huge increase instead. The web site below shows the statistics as a chart and explains more fully:
Alive and Well - see under "Rethinking AIDS", with the chart that shows how declining AIDS cases suddenly mushroomed in 1993 due to a redefinition.