Figure 2: Proportion and absolute frequency of HIV-1 patients treated with antiretroviral agents (ART). The absolute number of patients are plotted by year with percentage of patients on ART treatment represented by line chart. Zidovudine (AZT) monotherapy began in 1989 (n=20). Between 1990 and 1996, two NRTI combination was used (n=56). Beginning in 1996, a combination of three or four different antiretroviral drugs (HAART) was administered.