Population aged 18 and older

IBISWorld forecasts the population aged 18 and older to increase by 2.2% during 2023-24, to reach 21,357,108 people. Migration is a key determinant of growth in this demographic. The Australian Government's COVID-19 border restrictions limited immigration into Australia during the three years through 2021-22, constraining growth in this population demographic. However, the removal of border restrictions during the 2022 calendar has seen migration levels rebound, supporting growth in this population demographic in the previous and current year.

In general, the birth rate tends to be more volatile than overall population growth, with birth rates demonstrating periods of both growth and decline. However, over the past three decades, the birth rate has trended upwards and contributed to growth in the population aged 18 and older, as mortality rates among people aged 17 and younger are generally very low. In addition, life expectancy in Australia has continued to improve, supporting growth in the population demographic.

Over the past five years, the population aged 18 and older has grown at a consistent rate, despite a temporary blip during the pandemic. The key drivers of population growth for people in this age group are increasing life expectancy, net migration rates and the number of births 18 years prior. Overall, IBISWorld forecasts the population aged 18 and older to grow at a compound annual rate of 1.6% over the five years through 2023-24.