Monday, January 17, 2022

Population trends in South Australia

Australia's population continues to be influenced by the ongoing COVID-19 pandemic and the policy changes implemented to control the spread. Historically, South Australia has grown at a modest rate, and its population has an older age profile. But more recently, the state has recorded small gains from interstate migration. Will this make a difference to the ageing trend? 

What is the population?

At June 2021, the population of South Australia was 1.77 million, an increase of 0.2% over the previous year (2,970 people). This is the lowest volume and rate of growth recorded since the mid-1990s. By way of comparison, South Australia's population growth rate was 1.0% in the twelve months ended June 2020, or 17,600 persons. Like other states and territories, the closure of the international border has resulted in negative growth via overseas migration. 

The graph below shows the components of population change in South Australia since 1982. Overall, overseas migration and natural increase have driven growth in the last 40 or so years. Typically, South Australia loses residents to other parts of Australia when they move interstate. However, net interstate migration loss has diminished since 2016, and became positive (704 people) in 2020-21. This was the first time in 30 years that South Australia has recorded a gain of people through interstate migration. Between 2016 and 2021, the number of people moving to South Australia increased by 25% and in the last two years has been driven by people aged 45 years and over.



Net overseas migration (NOM) has been the main driver of population growth in South Australia since the mid 2000s. However the volume has been volatile, with a high of 18,000 in 2008-09. In 2020-21, NOM fell into negative territory (-3,280 persons) due to the closure of the international border.

The volume of natural increase has generally trended downward over the last 40 years, save for a brief increase in the decade after 2005. This corresponded with the sharp increase in NOM, and as a result, the number of births increased in line with an increased population of younger people. 

However, the number of deaths in South Australia has increased steadily over the last 40 years. This is due to an ageing population - in fact, South Australia is one of two states to have a median age exceeding 40 years (the other is Tasmania). Most deaths occur at the upper end of the age spectrum, so as the population of older people increases, a corresponding increase in the number of deaths tends to follow. In terms of population change, the result has been a gradual decline in the volume of natural increase. In 2018-19 and 2019-20, natural increase dropped below 5,000 for the first time in several decades. However it increased to 5,540 in 2020-21 but it remains to be seen if this is sustained.

South Australia's changing age structure

The graph below shows how the age structure has changed over the last 40 years. Between 1980 and 2020, the population of South Australia grew by about one-third, from 1.31 - 1.77 million. At the same time, the population aged significantly over this 40 year period. The population aged 50 years and over doubled, and comprised 38.1% of the population in 2020, compared to 25.6% in 1980. 
















Of course, the 50+ population is diverse in terms of generations, life stage and health status. Census data shows that people aged 75 years and over are more likely to have a disability that requires assistance with core activities. As such, this cohort has a stronger impact on the health system and associated services. In South Australia, the 75+ population has more than tripled since 1980, and now numbers more than 150,000. This cohort was born 1945 and earlier, and so don't include the baby boomer generation - yet. The graph above shows that this generation, aged roughly 55-74 years in 2020, are relatively large in number. As a result, their movement through the age spectrum will further contribute to the ageing of the population in the short to medium term.

In contrast, the population of younger people has declined since 1980, though there are some conflicting trends. This is a result of lower fertility as well as out migration of younger people. As a group, the population of people aged under 25 years declined slightly (-4%) between 1980 and 2020. However, most of this loss occurred between 1980 and 2000, when the population of this cohort fell to 488,180 persons. Since 2000, the population of under 25s has increased to 526,370. An increase in overseas migration has resulted in a 20% increase in the population of 20-24 year olds, many of whom are international students. Overseas migration has also increased the number of women in family forming age groups who are permanent arrivals, and as a result the population of children and young teenagers has increased. 

Overall however, despite increased gains in population via migration, the older population structure and the momentum behind this will continue to drive demographic change in South Australia. Young people comprise a smaller proportion of the population compared to 40 years ago, and there has been a corresponding increase in the proportion of older people. The median age continues to creep upwards, reaching 40.3 years in 2020. Although there have been small gains via interstate migration in the last year, this appears to be driven by people aged 45 years and over rather than young adults. This will only contribute to further ageing of the population. Whether this is mitigated by a resumption of overseas migration remains to be seen.

Summary

South Australia has one of the older age profiles in Australia, as indicated by its median age and high proportion of older people in the population. Between 1980 and 2020, the population grew by about one-third, but the increase in the older population was stronger. People aged 50+ doubled in number over the 40 year period. In contrast, there was a decline in the number of people aged under 25 years. The large cohort of baby boomers will contribute to further population ageing in the future, and despite the increase in interstate and overseas migration, this trend is unlikely to change.

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