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Feature Article - A Century of Population Change in Western Australia
In 1901, Western Australia's population was much younger than it is today and men outnumbered women by three to two. At that time, the 25-34 year age group represented 25% of the population, creating a visible bulge in the shape of the age-sex pyramid. Conversely, people aged 50 years and over represented only 8% of the population while those aged 65 years and over represented less than 2%. By the end of the century, the 25-34 age group accounted for only 15% of the population whereas the proportions aged 50 years and over and 65 years and over had increased to 26% and 11% respectively.
The sex ratio (number of males per 100 females) was 155.7 at the beginning of the twentieth century. This excess of males over females was primarily due to a higher proportion of males in the migrant intake during the preceding decades.
By the 1920s, an increase in the proportion of female migrants and troop fatalities in World War I resulted in a reduced proportion of males in the population. At the same time, mortality rates were generally decreasing as a result of improved standards of living. These factors had a considerable impact on the age-sex structure of the population. By 1933, people age 50 years and over represented 19% of the population and the sex ratio was 114 males for every 100 females.
By 1966, the excess of males over females in the general population had further decreased with 104.2 males for every 100 females. The post-war baby boom had impacted on the age-sex pyramid, with a large increase in the number of children under 15 years. Between 1901 and 1966, this age group had increased fivefold from 53,000 to 260,000.
By 1996, the sex ratio had almost achieved equilibrium (101.2 males per 100 females). However, the high masculinity of the migrant intake in the immediate post-war years was still reflected in the sex ratio for the 45-64 age group (105.3).
In the last three decades of the century, Western Australia's population aged significantly as a result of lower fertility and continuing falls in mortality. Between 1979 and 1996, the median age of the population rose from 29.1 to 33.1 years.
In 2000, 'baby boomers' born between 1945 and 1971, were estimated to represent over 40% of the state's population. The baby boom generation, being significantly larger than preceding and succeeding generations, will continue to impact on the age structure of the Western Australian population and to influence government policy for the next several decades. By 2031, they will be part of the population aged 60 years and over and are projected to represent over a quarter of the state's population.
In 1901, there were 30.4 births for every 1,000 persons in the estimated resident population. After 1906, this crude birth rate began a steady decline, dropping to 21.7 after World War I. In the 1920s, the rate remained steady but began to fall again at the start of the Depression, sinking to 17.6 by 1934. Thereafter, the rate began to rise slowly, peaking at 25.7 in 1952 and generally remaining above 20.0 until 1973. From that time, the crude birth rate fell rapidly, sinking to its lowest ever recorded level (13.4) by 1999.
The dramatic changes in the fertility of Western Australian women that occurred in the second half of the century are best illustrated by changes in the total fertility rate. This is defined as the number of children a woman would bear if the current age-specific fertility rates (number of live births to mothers at each age per 1,000 of the female population of that age) continued during her reproductive life. In the late 1940s, the start of the post-war baby boom, the total fertility rate reached 3.5 babies per woman and eventually peaked at 3.7 babies per woman in 1961.
In the 1960s, the introduction of oral contraception, changing preferences on family size and women's increasing participation in paid employment caused the total fertility rate to fall. By 1966, it had fallen to 3.1. In the 1970s, it continued to fall rapidly, and by 1977, had fallen below replacement level (2.1 babies per woman). By 1979, the total fertility rate was 1.97, gradually dropping to 1.76 by the end of the century.
This fall in fertility coincided with the trend towards delayed motherhood. Between 1976 and 1999, the median age of mothers increased, for all births, from 25.5 years to 29.4 years. This trend towards delayed motherhood can also be seen in the decreasing proportion of births to mothers aged 20-24 years, which fell from 21% of all births in 1990 to 17% in 1999. Over the same period, the proportion of births to mothers aged 30-34 years increased from 27% to 30%.
The life expectancy of both sexes increased throughout the century. However, females have a greater life expectancy than males and are estimated to have a genetic advantage of about two years of life (Hugo,1986). The remainder of the difference can be attributed to behavioural and lifestyle patterns.
The difference between male and female life expectancy at the beginning of the twentieth century was 5.1 years, being 51.4 years for males at birth and 56.5 years for females. By 1981, the difference had increased to 7.2 years, with a life expectancy of 72.1 years for males and 79.3 years for females. In the last two decades, the gap in life expectancy between males and females gradually narrowed to 5.7 years. By the end of the century, life expectancy at birth was 76.4 years for males and 82.1 years for females.
LIFE EXPECTANCY, Western Australia
Mortality rates in Western Australia declined throughout the twentieth century. The reduction in mortality in the early decades has been attributed to improvements in living standards resulting from better food, health education, water and sewerage systems. From 1901 to 1950, the crude death rate (number of deaths registered per 1,000 of the estimated resident population) fell from 13.4 to 9.1.
In the latter half of the century, the crude death rate dropped faster and further in Western Australia than in Australia. Continuing reductions in mortality since World War II have been attributed to improved social conditions and advances in medical technology, including immunisation and antibiotics (Jain,1994). By 1999, the crude death rate had declined to 5.9.
Declining mortality rates were most evident in the age group 0-12 months. Over the century, the infant mortality rate (number of deaths of children under one year of age per 1,000 live births) fell from 128.9 to 4.7.
During the twentieth century, the crude marriage rate (annual number of registered marriages per 1,000 of the estimated resident population) fell in times of economic recession and increased during and immediately after the two world wars. In 1901, the crude marriage rate was 9.7, increasing to 11.4 by 1942, the highest on record for the state. Later in the century, the crude marriage rate fell, declining from 9.4 in 1969 to 5.5 in 1999.
The decline in the popularity of registered marriage in recent decades is associated with a rise in the incidence of de facto marriage. By 1999, de facto marriages accounted for 11% of all couple relationships. The proportion of de facto marriages was highest among people aged 25-29 years and was also high in the age groups 20-24 years and 30-34 years. The 1992 ABS Survey of Families found that, of the people living in de facto relationship, 70% had never been in a registered marriage, 22% were divorced and 7% were separated.
During the last three decades of the twentieth century, there was a growing trend among Western Australians to marry later in life. In 1977, the median age at first marriage was 21.1 years for brides and 23.7 years for bridegrooms. By 1999, this median age had increased to 26.5 years for brides and 28.5 years for bridegrooms.
MEDIAN AGE AT FIRST MARRIAGE, Western Australia
The number of divorces in Western Australia remained relatively low prior to the passage of the Family Law Act (1975) which made irretrievable breakdown of marriage the sole ground for divorce.
In most years prior to 1976, the crude divorce rate (annual number of decrees made absolute per 1,000 of the estimated resident population) remained below 1.0. However, in the years following World War II the divorce rate did increase slightly, reaching 1.6 in 1948.
The crude divorce rate peaked at 4.6 in 1976 as a backlog of divorces was cleared following the passage of the Act. By 1979, the crude divorce rate had stabilised around 2.7.
Although Western Australia is home to only 10% of the nation's population, it has generally attracted a higher share of net overseas migration. Since the 1970s, its share of permanent and long term overseas arrivals has been fairly stable, at 13% and 11% respectively.
Mobility within Australia appears to have been high throughout the century. It has been estimated that, on average, Australians will move eleven times during their lifetime, if 1985-86 migration rates and 1985-87 mortality rates are maintained (Bell,1996).
In the last quarter of the century, interstate migration was characterised by a northward and westward drift away from the south-eastern corner of Australia, resulting in large net population gains for Queensland and Western Australia in some years. However, annual interstate migration into Western Australian has been quite volatile, ranging from a gain of 9,100 persons in 1976 to a loss of 1,800 persons in 1991.
The largest fluctuations in migration (when net interstate and overseas migration are combined) occurred prior to World War II, with population losses exceeding gains in some years. In the second half of the century, Western Australia consistently gained population from migration.
The changing composition of Western Australia's population reflects the migration waves that occurred over the last century. The clearest trend over the last hundred years is the relative decline in the significance of the United Kingdom as a source country and the increasing diversity of birthplaces represented in the population. In 1901, 31% of Western Australians had been born overseas: of those, 45% had been born in England.
Prior to World War II, migrants from the United Kingdom and Ireland, who travelled on assisted passages, dominated the flow into the state and the nation. By 1911, the only significant change was an increase in the number of migrants from South Africa, arriving as a consequence of Australia's intervention in the Boer War. Net overseas migration fell below zero during the economic depression of the 1930s and the two world wars.
WESTERN AUSTRALIAN POPULATION BORN OVERSEAS, Top Six Countries - 1901
Following World War II, Australia welcomed high levels of immigration as a rapidly growing population was seen as essential to continued economic success. In Western Australia, the first wave of post-war migrants occurred between 1947 and 1957 and largely comprised migrants from the United Kingdom and Italy, as well as displaced persons from northern and eastern Europe. By 1954, the proportion of the overseas-born population born in England had declined to 42% while those born in Italy had grown to be the second largest group (12%).
WESTERN AUSTRALIAN POPULATION BORN OVERSEAS, Top Six Countries - 1954
The second, larger wave of migrants occurred between 1962 to 1971 and drew more heavily on the Mediterranean countries including Italy, Greece, Malta and Egypt. During this time, however, migrants from England continued to dominate numerically.
In the last thirty years of the century, patterns of migration changed as a result of the abolition of the White Australia Policy. In 1973, the Immigration Restriction Act (1901), the Pacific Islanders Labourers Act (1901) and the Naturalisation Act (1903) were replaced by non-discriminatory immigration policies. As a result of these policy changes, migrants from a greater variety of countries, especially southern and south-east Asian countries, settled in Western Australia.
WESTERN AUSTRALIAN POPULATION BORN OVERSEAS, Top Six Countries - 1976
Towards the end of the twentieth century, people born in southern and south-east Asia increased significantly as a share of the migrant intake into Western Australia. By 1996, India and Malaysia were both represented in the top six source countries, accounting for 3% and 4% respectively of the overseas-born. While England remained a dominant source country, those born in England had decreased as a proportion of the overseas-born from 47% to 36% in the twenty years to 1996.
WESTERN AUSTRALIAN POPULATION BORN OVERSEAS, Top Six Countries - 1996
Bell, M. 1996, 'How often do Australians move? Alternative measures of population.
Hugo, G.J. 1986, Australia's Changing Population: Trends and Implications, Oxford University Press, Melbourne.
Jain, S.K. 1994, Trends in Mortality, National Centre for Epidemiology and Population and the Australian Bureau of Statistics, Canberra.
The statistics used in this article are sourced from the ABS Ausstats release Australian Historical Population Statistics. For further information, contact Zaneta Georgievski on (08)9360 5271 or by email at email@example.com
POPULATION STATISTICS, Western Australia: 1901 to 2000
PRINTER FRIENDLY VERSION OF "A CENTURY OF POPULATION CHANGE IN WESTERN AUSTRALIA"
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