Im sure if you take the time to actually research the truth you will find it. Try the
How is the U.S. relavant to Australia, god almighty Hawkers, really im not going to go back to basics and chase information for you, do it yourself. If you don't know why the U.S. example is relevant then perhaps you shouldn't be in the property market!!
There is lots of useful historic data and sights around if you would only look, I know Ive looked.