Almost 21 million people around the world are now getting life-prolonging AIDS drugs, according to a report issued on Monday. But another 16 million people infected with H.I.V. are not yet on medication.

The report was released in South Africa by Unaids, the joint United Nations AIDS-fighting agency.

Antiretroviral triple therapy became standard in wealthy countries in 1996, but it took almost a decade for just one million people in poor countries to receive treatment.

That happened only after generic drugs became available and donor organizations like the Global Fund to Fight AIDS, Tuberculosis and Malaria were created to pay for them.

Unaids has set a goal called “90-90-90” by 2020. That is: 90 percent of the world’s H.I.V.-infected people having had an H.I.V. test; 90 percent of those who test positive having been prescribed drugs; and 90 percent of those prescribed drugs staying on them faithfully enough to have undetectable levels of the virus in their blood.