comparing aus house prices to other countries, page-33

To my knowledge it is calculated on AWOTE - Average Weekly Ordinary Time Earnings.

But maybe it's changed.

Either way, the median is used rather than the mean, same as the house prices.

This minimises any skew from huge earnings or house prices.

The data has been collated for a long time and would be pretty accurate one would think, especially with computers doing all the number crunching.