Assets here include financial assets, and physical assets (mainly the dwelling stock). For many years, assets were about 4 times annual income. Over the past 15 years, that has risen to about 7 times. That is quite a striking result.
It is at least as large, for example, as the relative increase in assets of American households, which occurred in the stock market boom there in the late 1990s. The difference is that, in Australia, much of this increase in asset values, particularly over the past few years, has been a result of rising house prices.