Population
Service age groups
About this topic
Service age groups divide the population into broad life-stage bands such as children, young adults, working-age adults, and older people. The groupings are designed to reflect typical demand for age-based services and facilities rather than exact five-year cohorts.
This view is useful for planning childcare, schools, recreation, aged services, and other community infrastructure. It works best alongside five year age groups, household type, and dwelling data, which add more detail about who is living in an area and how needs may change over time.
Interpretation notes
- This is a derived grouping rather than a direct Census question, so the age bands are planning-oriented summaries built from standard age data.
- Percentages relate to the total population; use five year age groups when exact cohort detail matters.
Related topics
Key insight
In 2021, Parents and homebuilders (35 to 49) was the most common category among residents in Blacktown (C), accounting for 23.4% (92,798 people). This share was higher than Greater Sydney (21.5%). Since 2016, the biggest change was in Parents and homebuilders (35 to 49), which increased by 19,613 people and 1.7 percentage points.
Section overview
Age structure - Service age groups
Blacktown (C) - Total persons (Usual residence)
This table summarises service age groups for Blacktown (C) in 2021 for persons, with comparison against Greater Sydney and change since 2016.
Age structure - Service age groups snapshot
2021 distribution by category for Blacktown (C), with comparison markers for Greater Sydney.
Babies and pre-schoolers (0 to 4)
2021 count
29,909
% of total
7.5%
Change from 2016
-0.5pp
29,909
7.5%
-0.5pp
Primary schoolers (5 to 11)
2021 count
43,425
% of total
10.9%
Change from 2016
+0.1pp
43,425
10.9%
+0.1pp
Secondary schoolers (12 to 17)
2021 count
31,676
% of total
8.0%
Change from 2016
-0.2pp
31,676
8.0%
-0.2pp
Tertiary education and independence (18 to 24)
2021 count
35,926
% of total
9.1%
Change from 2016
-0.4pp
35,926
9.1%
-0.4pp
Young workforce (25 to 34)
2021 count
59,260
% of total
14.9%
Change from 2016
-0.6pp
59,260
14.9%
-0.6pp
Parents and homebuilders (35 to 49)
2021 count
92,798
% of total
23.4%
Change from 2016
+1.7pp
92,798
23.4%
+1.7pp
Older workers and pre-retirees (50 to 59)
2021 count
42,325
% of total
10.7%
Change from 2016
-0.7pp
42,325
10.7%
-0.7pp
Empty nesters and retirees (60 to 69)
2021 count
32,502
% of total
8.2%
Change from 2016
-0.2pp
32,502
8.2%
-0.2pp
Seniors (70 to 84)
2021 count
24,682
% of total
6.2%
Change from 2016
+0.8pp
24,682
6.2%
+0.8pp
Elderly aged (85 and over)
2021 count
4,303
% of total
1.1%
Change from 2016
0.0pp
4,303
1.1%
0.0pp
Chart view
Age structure - Service age groups change
Absolute change in category counts between 2016 and 2021.
Babies and pre-schoolers (0 to 4)
+2,987
-0.5pp
Primary schoolers (5 to 11)
+7,178
+0.1pp
Secondary schoolers (12 to 17)
+4,089
-0.2pp
Tertiary education and independence (18 to 24)
+3,899
-0.4pp
Young workforce (25 to 34)
+7,015
-0.6pp
Parents and homebuilders (35 to 49)
+19,613
+1.7pp
Older workers and pre-retirees (50 to 59)
+3,857
-0.7pp
Empty nesters and retirees (60 to 69)
+4,033
-0.2pp
Seniors (70 to 84)
+6,424
+0.8pp
Elderly aged (85 and over)
+744
0.0pp
Data table
Service age groups for Blacktown (C). Age structure - Service age groups. 2021 and 2016 counts, percentages, and change compared with Greater Sydney.
| Category | 2021 | 2016 | Change | |||||
|---|---|---|---|---|---|---|---|---|
| Count | % | Greater Sydney% | Count | % | Greater Sydney% | Count | pp | |
| Babies and pre-schoolers (0 to 4) | 29,909 | 7.5% | 6.0% | 26,922 | 8.0% | 6.4% | +2,987 | -0.5pp |
| Primary schoolers (5 to 11) | 43,425 | 10.9% | 8.8% | 36,247 | 10.8% | 8.8% | +7,178 | +0.1pp |
| Secondary schoolers (12 to 17) | 31,676 | 8.0% | 7.1% | 27,587 | 8.2% | 6.9% | +4,089 | -0.2pp |
| Tertiary education and independence (18 to 24) | 35,926 | 9.1% | 8.8% | 32,027 | 9.5% | 9.6% | +3,899 | -0.4pp |
| Young workforce (25 to 34) | 59,260 | 14.9% | 15.5% | 52,245 | 15.5% | 16.1% | +7,015 | -0.6pp |
| Parents and homebuilders (35 to 49) | 92,798 | 23.4% | 21.5% | 73,185 | 21.7% | 21.1% | +19,613 | +1.7pp |
| Older workers and pre-retirees (50 to 59) | 42,325 | 10.7% | 12.0% | 38,468 | 11.4% | 12.2% | +3,857 | -0.7pp |
| Empty nesters and retirees (60 to 69) | 32,502 | 8.2% | 9.8% | 28,469 | 8.4% | 9.5% | +4,033 | -0.2pp |
| Seniors (70 to 84) | 24,682 | 6.2% | 8.7% | 18,258 | 5.4% | 7.5% | +6,424 | +0.8pp |
| Elderly aged (85 and over) | 4,303 | 1.1% | 2.0% | 3,559 | 1.1% | 2.0% | +744 | 0.0pp |
| Total | 396,776 | 100.0% | 100.0% | 336,962 | 100.0% | 100.0% | +59,814 | 0.0pp |