 Australian Bureau of Statistics, Australian Taxation Office and many other Federal and State government organisations publish a variety of statistics by postcode which extends the use Australia Post four digit code to many business and social planning related activities.There is an inherent problem with spatial representation of postcodes since areas referenced to a specific postal code tend to change over time, as new postcodes are added or existing ones are split by Australia Post for operational purposes.Some mail generating software can automatically sort outward mail by postcode before it is generated.