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 Black Rock (Vic.), accounting for 16.9% (1,078 people). This share was lower than Bayside (C) (19.4%). Since 2016, the biggest change was in Parents and homebuilders (35 to 49), which decreased by 1,831 people and 4 percentage points.
Section overview
Age structure - Service age groups
Black Rock (Vic.) - Total persons (Usual residence)
This table summarises service age groups for Black Rock (Vic.) in 2021 for persons, with comparison against Bayside (C) and change since 2016.
Age structure - Service age groups snapshot
2021 distribution by category for Black Rock (Vic.), with comparison markers for Bayside (C).
Babies and pre-schoolers (0 to 4)
2021 count
249
% of total
3.9%
Change from 2016
-1.3pp
249
3.9%
-1.3pp
Primary schoolers (5 to 11)
2021 count
503
% of total
7.9%
Change from 2016
-0.5pp
503
7.9%
-0.5pp
Secondary schoolers (12 to 17)
2021 count
544
% of total
8.5%
Change from 2016
+0.8pp
544
8.5%
+0.8pp
Tertiary education and independence (18 to 24)
2021 count
461
% of total
7.2%
Change from 2016
-1.9pp
461
7.2%
-1.9pp
Young workforce (25 to 34)
2021 count
391
% of total
6.1%
Change from 2016
-6.3pp
391
6.1%
-6.3pp
Parents and homebuilders (35 to 49)
2021 count
1,078
% of total
16.9%
Change from 2016
-4.0pp
1,078
16.9%
-4.0pp
Older workers and pre-retirees (50 to 59)
2021 count
1,057
% of total
16.5%
Change from 2016
+3.3pp
1,057
16.5%
+3.3pp
Empty nesters and retirees (60 to 69)
2021 count
939
% of total
14.7%
Change from 2016
+5.2pp
939
14.7%
+5.2pp
Seniors (70 to 84)
2021 count
942
% of total
14.7%
Change from 2016
+5.3pp
942
14.7%
+5.3pp
Elderly aged (85 and over)
2021 count
210
% of total
3.3%
Change from 2016
-0.8pp
210
3.3%
-0.8pp
Chart view
Age structure - Service age groups change
Absolute change in category counts between 2016 and 2021.
Babies and pre-schoolers (0 to 4)
-469
-1.3pp
Primary schoolers (5 to 11)
-663
-0.5pp
Secondary schoolers (12 to 17)
-535
+0.8pp
Tertiary education and independence (18 to 24)
-813
-1.9pp
Young workforce (25 to 34)
-1,336
-6.3pp
Parents and homebuilders (35 to 49)
-1,831
-4.0pp
Older workers and pre-retirees (50 to 59)
-781
+3.3pp
Empty nesters and retirees (60 to 69)
-390
+5.2pp
Seniors (70 to 84)
-375
+5.3pp
Elderly aged (85 and over)
-365
-0.8pp
Data table
Service age groups for Black Rock (Vic.). Age structure - Service age groups. 2021 and 2016 counts, percentages, and change compared with Bayside (C).
| Category | 2021 | 2016 | Change | |||||
|---|---|---|---|---|---|---|---|---|
| Count | % | Bayside (C)% | Count | % | Bayside (C)% | Count | pp | |
| Babies and pre-schoolers (0 to 4) | 249 | 3.9% | 4.4% | 718 | 5.2% | 5.1% | -469 | -1.3pp |
| Primary schoolers (5 to 11) | 503 | 7.9% | 8.6% | 1,166 | 8.4% | 9.7% | -663 | -0.5pp |
| Secondary schoolers (12 to 17) | 544 | 8.5% | 8.7% | 1,079 | 7.7% | 8.2% | -535 | +0.8pp |
| Tertiary education and independence (18 to 24) | 461 | 7.2% | 7.8% | 1,274 | 9.1% | 7.4% | -813 | -1.9pp |
| Young workforce (25 to 34) | 391 | 6.1% | 7.8% | 1,727 | 12.4% | 8.2% | -1,336 | -6.3pp |
| Parents and homebuilders (35 to 49) | 1,078 | 16.9% | 19.4% | 2,909 | 20.9% | 21.4% | -1,831 | -4.0pp |
| Older workers and pre-retirees (50 to 59) | 1,057 | 16.5% | 15.7% | 1,838 | 13.2% | 14.9% | -781 | +3.3pp |
| Empty nesters and retirees (60 to 69) | 939 | 14.7% | 12.1% | 1,329 | 9.5% | 11.5% | -390 | +5.2pp |
| Seniors (70 to 84) | 942 | 14.7% | 12.2% | 1,317 | 9.4% | 9.9% | -375 | +5.3pp |
| Elderly aged (85 and over) | 210 | 3.3% | 3.4% | 575 | 4.1% | 3.7% | -365 | -0.8pp |
| Total | 6,389 | 100.0% | 100.0% | 13,940 | 100.0% | 100.0% | -7,551 | 0.0pp |