The 7 must-know numbers of the week

The amount by which American self-described "real estate expert" Jordan Wirsz predicts Australian house prices will fall in the next five years. Prominent property doom commentator Steve Keen  expressed ironic relief via Twitter that another analyst has forecast even worse tidings than his longstanding forecast for the Australian property market.

The annual capital growth in Prahran during 2011, the highest capital growth in Victoria during the year.

The overall drop in Melbourne house prices in 2011, according to the Real Estate Institute of Victoria. The institute puts the median house price at $550,000, a minor increase of 1.9% from the revised September quarter median of $540,000, but 5.2% down on a median of $580,000 a year ago.

Sydney's rank on the list of the most unaffordable cities in the world, according to the Eighth Annual Demographia International Housing Affordability Survey. Melbourne is ranked fourth, and Adelaide, Brisbane and Perth are all in the top 15. 

The amount of money that offshore Chinese buyers spent on Gold Coast property during the 2010-11 financial year. Chinese buyers accounted for nearly a third of foreign purchases of Queensland residential real estate during the 2010-11 financial year

The amount Nicole Kidman has hoped to secure for her landholding on the NSW far south coast since 2008. She will auction the property next month.

The sale price Singaporean businessman Ronald Ooi paid for Dame Joan Sutherland's childhood home, a derelict cottage in Woollahra. Several years before her death Sutherland noted: "Unfortunately, from the time my family gave up the house, the deterioration set in.”