City truly young at heart, oldies coasting along

If you would rather have older people as your neighbours, in the extended Melbourne area, they don't come any older than the good folk of Rosebud. Their average age is 50.7 years old, almost 15 years older than people living in your average Melbourne suburb. Almost one in three of them is over 65.

But if it's the young cool dudes you like having around you, then move into Parkville. The average age there is just 25, just a few months younger than Carlton (25.5) or the CBD (26.7).

All the demographic details collected in the 2011 census are now pouring out of the Bureau of Statistics.

They tell us that in Taylors Hill, 28.2 per cent of the population is aged under 15, whereas in Southbank it's just 4.8 per cent, and in the CBD, 3.5 per cent the lowest proportion in Victoria.

The youngest area of Australia is Northern Territory community Thamamurr, including the big coastal town of Wadeye. The average age of its 2682 inhabitants is just 21.6 years old. Just 1.9 per cent are over 65, whereas 36 per cent are under 15 years old.

Australia's oldest community is Tuncurry, the retirement haven on the mid-north coast of New South Wales. Almost 40 per cent of its inhabitants are over 65, and the average age is 58.8.

Our oldest communities live on the shores of our oceans, bays and lakes. In Victoria, it's Paynesville, on the Gippsland Lakes, where your average neighbour is 56.1 years old, just out-ageing Portarlington (54.4) and Queenscliff (54.1).

Younger Australians head for the big cities. The census found 38 per cent of people in the cities are aged 20 to 44, but just 31 per cent are 20 to 44 in the rest of Australia.

University suburbs have the youngest urban populations: after Parkville, Carlton and the CBD, the next youngest suburb is Clayton (Monash). Then there's a quite different group of young families on the suburban fringe: the average age is also under 30 out west in Roxburgh Park, Tarneit and Truganina.

These are suburbs where more than one in four residents is a child under 15, and old people are rare. In Truganina, north of Laverton, just 2 per cent of people are over 65, whereas 25 per cent are under 25.