The SR Structure has been in use since 1986 for the production of standard statistical outputs from Population Censuses and labour force surveys. Labour Force Surveys use dissemination regions for the publication of labour force data.
SRs are maintained as a separate structure from the Main Structure because of the complex manner in which they relate to SSDs and SDs. For example, SRs can be whole SSDs, aggregates of SSDs, or part of an SSD. Similarly they can be whole SDs, aggregates of SDs or part of an SD. SRs can also be as large as a state or territory. SRs are aggregates of SLAs.