Raw numbers and most of the terms ("disposable", etc.) are found in
www.ausstats.abs.gov.au/ausstats/subscriber.nsf/0/FB162A8CBB41033DCA257BCD001A5725/$File/65540_2011_12.pdfIt's actually not unclear.

I was going to discount, on the basis that the top 1% are billionnaires and would have skewed the averages (not medians).
But the methodology is a survey of some 15k households, and since the odds of a zillionnaire answering this type of questionnaire are slim, then it becomes worthy reading. I was put off by NT having such top weekly earnings - suspicious, no? The presentation seems to work backwards from a Pareto "let's use the 80-20 imagery to exemplify what we wanna say".
55yo+ hold half the national wealth. This is not bad: means all this will be redistributed soon to younger types, either through consumerism or just plain dying. Unfortunately, part of that late-life consumerism just leaves the country - travelling, bying exports, etc. The 35-44 seem to be on par to catch up with the lifestyle of the 45+ group - if the economy continues, if taxes don't rise, and if they can keep their job - a series of tall if's... However presumably they will inherit soon from the groups above, which are rather sizeable in numbers at 26%.
Hard to see the 25-34 catching up, esp. that they're spending like crazy and not saving (or can't because of the housing market). But maybe I'm missing something.
A comparison of similar data with the Yanks would be interesting...