A blog (mostly) about death

Following on from the annual release of births data, yes you guessed it – the ABS recently released Deaths, Australia (Cat. no. 3302.0).  This release contains statistics on the number and characteristics of deaths in Australia, including data for small geographic areas such as LGAs.  Similar to births, data on deaths forms a critical component of our population forecasts.  This blog will summarise some of the main points from this year’s release.

How many people die in Australia?

In 2011, there were 146,932 deaths in Australia.  The number of deaths was relatively stable throughout the 1990s, but since 2000 the number of deaths has been increasing.  Australia’s population has of course increased over this time, thereby increasing the potential for more deaths, but the ageing of the population, and the size of particular population cohorts also has an impact on the numbers.  For instance, the increase over the last decade relates to the ageing of the population and the increasing size of the cohorts moving through the age spectrum ie more people reaching an age at which death is more likely.

It might surprise some people that the median age of death is quite high and has been increasing over the last decade.  In 2001, the median age at death was 78.5 years, but in 2011 it was 81.5 years.  In other words, half of deaths were of people aged more than this, and half under.  There was some difference between males and females – in 2011 the median age at death for males was 78.4 years and for females 84.5 years.  This reflects differences in life expectancy (see below) but also differences in causes of death – for instance it is a well established fact that young adult males are more likely to die as a result of car accidents.  These sorts of differences occur throughout the life cycle.

Where do most deaths occur?

There are variations in death rates across the country and they are correlated with variables such as age structure and Indigenous status.  These factors certainly contribute to slightly higher death rates in regional areas of Australia.  The table below shows the indirect standardised death rate for metropolitan and regional areas across Australia in 2011.

The death rate of the Balance of Northern Territory stands out as being particularly high.  It is somewhat influenced by the small population and subsequent statistical volatility but also the high proportion of Indigenous people (who have lower life expectancy) is certainly a factor.

As mentioned above, the ABS does publish deaths data for LGAs.  However, the very small number of deaths in some LGAs mean that the rates can be skewed significantly.  At .id, when we formulate assumptions about death rates in an LGA in the future, we tend to amalgamate surrounding areas (perhaps 3 LGAs) in order to get a statistically meaningful distribution of data across the age spectrum.

Life expectancy

Life expectancy is generally defined at the expected number of years a person has left to live, given current age-specific mortality rates.  It is most frequently expressed as life expectancy at birth ie how many years a new born baby can expect to live, but you can calculate life expectancy at any age (refer life tables).  Improvements to health and sanitation over the last century have contributed to great increases in life expectancy and this is one of the primary reasons for the ageing of the population.  By a quirk of biology, females have greater life expectancy than males (but there are more males born than females – another quirk).  According to the ABS, in the first decade of the twentieth century, males had a life expectancy of 55.2 years and females 58.8 years.  By mid century this had increased to 66.1 years for males and 70.6 years for females.  In 2011, new born baby boys could expect to reach 79.7 years, and baby girls 84.2 years – many of them will no doubt see the 22nd century!

Natural increase

The difference between the number of births and deaths is called natural increase – and of course if there are more deaths than births it might be called natural decrease.  It is a critical component of population change simply because it determines, in the absence of any migration, whether a population will grow or decline.  An area that records natural decrease can only grow if there is sufficient net in-migration to cover the difference between births and deaths.  This is critical in explaining population change in some parts of Australia.

The map below (click for a large version) shows the extent of natural increase (or decrease) in Victorian LGAs in 2011.  Orange shaded areas recorded natural increase, and the darker orange areas are those that recorded the highest volume.  The spatial distribution of these is quite clear – areas with the most natural increase were located in Melbourne.  We’ve said it before and we’ll say it again – Melbourne has a young population with a large pool of women who are of prime reproductive age (nice technical term!), and this is fuelled by overseas migration.  As a result birth numbers are high and in those parts of Melbourne that have few elderly people and hence relatively low death numbers, natural increase will be high.

LGAs that recorded the highest volume of natural increase in 2011 were Casey (2,859) and Wyndham (2,645), both fringe areas experiencing rapid growth.  In fact, Wyndham has recently been in the news recently regarding the ability of local hospitals to deal with all the births in the region.

Areas shaded mushroom recorded natural decrease.  No LGAs in Melbourne recorded natural decrease, but the same cannot be said of regional Victoria.  Much of the west and north west, parts of central Victoria and the far east, recorded more deaths than births in 2011.  Many of these places have been recording population loss over a long period of time – high proportions of elderly people and out migration of youth are common themes.  The highest amount of natural decrease was recorded in Central Goldfields (-59) and Benalla (-55).  Both these LGAs recorded population decline between 2010 and 2011, so clearly any net in-migration was not enough to offset the difference between births and deaths.  In contrast, East Gippsland recorded natural decrease, but it’s population grew in the last year, so clearly net in-migration plays a role in explaining population change in this part of Victoria.

Access more information about the Australian Census 2011.

Access the new profile.id sites and other population statistics for Australia, States, Capital Cities, Local Government Areas and suburbs at .id’s demographic resource centre.