Census subdivision
For administration purposes, each census division is divided into census subdivisions. Each is represented by a two digit numeric code allocated sequentially, from 0 1. Each census subdivision consists of approximately 12 to 15 collection districts. Where 1981 Census subdivisions have not been altered within a census division, their codes were retained for 1986 where possible. Where alterations have occurred, the subdivisions have been renumbered. When renumbering of an area occurs, the first number is allocated to the most north-westerly segment. Numbering then proceeds in a serpentine fashion from west to east, then east to west, gradually moving south.