people have HIV, it actually depends where you look (ie. which country) and what
you compare it to.
For example, if you look
at another virus, CMV, which can be transmitted sexually or through saliva and via breast milk, we're talking about 30-100% of the population have it, again depending on which country and which age group you look at. This means worldwide, it probably has infected 2-3 billion people. Luckily, CMV doesn't do anything to you except when you get immune compromised.