But the weights used in the CPI are only updated each time the ABS conducts a Household Expenditure Survey, which, in recent times, has been every five or six years. In between each household expenditure survey, a number of things can happen. First of all, some new goods and services can come along that weren't there before.
Similarly, evidence of an isolated foreign debt servicing problem can be magnified into a generalised “rush for the exits”. The crisis which follows almost always seems to push the domestic currency beyond an equilibrium level with damaging social consequences.