So this is a graph of prevalence estimated by UNAIDS, and prevalence based on the mortality data for the years in the late 1990s in nine countries in Africa.
这是一个由联合国艾滋病联合工作组统计的感病数据 另外一个是用死亡率估测出来的 在九十年代末非洲十九个国家中的感染率数据