The “interbank rate” refers to the foreign exchange rate paid by banks when trading currencies with other banks. It also happens to be the lowest rate available at any particular time, and it is reserved specifically for large banking institutions. Individual forex transactions have a “spread” built in. The “spread” is the difference between the forex rate you pay and the interbank rate. Foreign exchange providers make money off the spread and/or by charging a commission.
Over that time, housing prices rose upwards of 7% per year, leaving the country with some of the most expensive real estate in the world -- as measured by the comparison of house prices to household incomes or Price Income Ratio (PIR).
Perhaps the initial driver of the growth was deregulation of the financial markets in the 1980s and 1990s that made credit more widely available, leading Australians to borrow more for housing, which drove up prices. The market continued to surge ever since; even avoiding a crash during the Great Recession