Dictionary, Census of Population, 2016
'Age' refers to the age of a person (or subject) of interest at last birthday (or relative to a specified, well-defined reference date).
Age categories by five-year age groups
2016, 2011, 2006, 2001, 1996, 1991, 1986 and 1981. For availability prior to 1981, please refer to Appendix 2.0 regarding date of birth and age.
Derived variable: Question 3
In 1991 and earlier censuses, the components of date of birth (day, month and year of birth) were either not all asked on the questionnaire (1971 and earlier) or not retained for dissemination (1981 to 1991). For example, in 1971 and 1976, the question on date of birth was answered in groups of months: January to May or June to December. In 1961 and 1966, respondents were only asked to state their age. In 1961, published data for single years of age were graduated (or smoothed) within each five-year age group to counteract the tendency towards 'heaping' at certain specific ages. In 1966, this was not done.