The geographical location is reported using a seven digit numerical code. The first digit is the single digit code to indicate state or territory. The remaining six digits are the numerical code for the Collection District (CD) within the state or territory.
The single digit codes for the states and territories and the six digit codes for the CDs are as defined in the Australian Standard Geographical Classification (ASGC).
The ASGC is updated on an annual basis with a date of effect of 1 July each year. The codes for CDs are unique within each state and territory, but not within the whole country. Thus, to define a unique location, the code of the state or territory is required in addition to the code for the CD.