This FACT indicates the median age of each Australian capital city. Australia is currently going through a transition stage, meaning the population on the whole is ageing. This is partly explained by the fact that the baby boomers of the mid 20th century are now growing older, leaving behind a smaller proportion of a younger population due to families having fewer children. Migration also has an impact, since most immigrants who are naturalised are adults, or approaching adulthood. The city with the highest median age is Hobart, at 39. Australia's youngest capital city is Darwin, with a median at 33 years old.