According to the search results, the percentage of koalas that have chlamydia varies depending on the location. In some parts of Australia, up to 90% of the koala population is infected with chlamydia. In other areas, the infection rate can be as high as 100% . However, it is important to note that the percentage of infected koalas can change over time due to factors such as habitat destruction, climate change, and the spread of the disease.