 Economists posit that commodity prices are the dominant driver of the Australian dollar, and this means changes in exchange rates of the Australian dollar occur in ways opposite to many other currencies.For decades, Australia's balance of trade has depended primarily upon commodity exports such as minerals and agricultural products.This means the Australian dollar varies significantly during the business cycle, rallying during global booms as Australia exports raw materials, and falling during recessions as mineral prices slump or when domestic spending overshadows the export earnings outlook.