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 Derrimut, accounting for 28.3% (2,449 people). This share was higher than Brimbank (C) (19.9%). Since 2016, the biggest change was in Young workforce (25 to 34), which decreased by 381 people and 5.2 percentage points.
Section overview
Age structure - Service age groups
Derrimut - Total persons (Usual residence)
This table summarises service age groups for Derrimut in 2021 for persons, with comparison against Brimbank (C) and change since 2016.
Age structure - Service age groups snapshot
2021 distribution by category for Derrimut, with comparison markers for Brimbank (C).
Babies and pre-schoolers (0 to 4)
2021 count
693
% of total
8.0%
Change from 2016
-4.9pp
693
8.0%
-4.9pp
Primary schoolers (5 to 11)
2021 count
1,256
% of total
14.5%
Change from 2016
+0.6pp
1,256
14.5%
+0.6pp
Secondary schoolers (12 to 17)
2021 count
868
% of total
10.0%
Change from 2016
+2.9pp
868
10.0%
+2.9pp
Tertiary education and independence (18 to 24)
2021 count
659
% of total
7.6%
Change from 2016
+0.4pp
659
7.6%
+0.4pp
Young workforce (25 to 34)
2021 count
1,169
% of total
13.5%
Change from 2016
-5.2pp
1,169
13.5%
-5.2pp
Parents and homebuilders (35 to 49)
2021 count
2,449
% of total
28.3%
Change from 2016
+1.9pp
2,449
28.3%
+1.9pp
Older workers and pre-retirees (50 to 59)
2021 count
813
% of total
9.4%
Change from 2016
+1.5pp
813
9.4%
+1.5pp
Empty nesters and retirees (60 to 69)
2021 count
476
% of total
5.5%
Change from 2016
+1.5pp
476
5.5%
+1.5pp
Seniors (70 to 84)
2021 count
233
% of total
2.7%
Change from 2016
+1.0pp
233
2.7%
+1.0pp
Elderly aged (85 and over)
2021 count
19
% of total
0.2%
Change from 2016
-0.1pp
19
0.2%
-0.1pp
Chart view
Age structure - Service age groups change
Absolute change in category counts between 2016 and 2021.
Babies and pre-schoolers (0 to 4)
-372
-4.9pp
Primary schoolers (5 to 11)
+109
+0.6pp
Secondary schoolers (12 to 17)
+282
+2.9pp
Tertiary education and independence (18 to 24)
+62
+0.4pp
Young workforce (25 to 34)
-381
-5.2pp
Parents and homebuilders (35 to 49)
+268
+1.9pp
Older workers and pre-retirees (50 to 59)
+159
+1.5pp
Empty nesters and retirees (60 to 69)
+143
+1.5pp
Seniors (70 to 84)
+90
+1.0pp
Elderly aged (85 and over)
-4
-0.1pp
Data table
Service age groups for Derrimut. Age structure - Service age groups. 2021 and 2016 counts, percentages, and change compared with Brimbank (C).
| Category | 2021 | 2016 | Change | |||||
|---|---|---|---|---|---|---|---|---|
| Count | % | Brimbank (C)% | Count | % | Brimbank (C)% | Count | pp | |
| Babies and pre-schoolers (0 to 4) | 693 | 8.0% | 5.6% | 1,065 | 12.9% | 6.7% | -372 | -4.9pp |
| Primary schoolers (5 to 11) | 1,256 | 14.5% | 8.3% | 1,147 | 13.9% | 8.3% | +109 | +0.6pp |
| Secondary schoolers (12 to 17) | 868 | 10.0% | 6.8% | 586 | 7.1% | 7.1% | +282 | +2.9pp |
| Tertiary education and independence (18 to 24) | 659 | 7.6% | 9.2% | 597 | 7.2% | 10.4% | +62 | +0.4pp |
| Young workforce (25 to 34) | 1,169 | 13.5% | 15.7% | 1,550 | 18.7% | 16.1% | -381 | -5.2pp |
| Parents and homebuilders (35 to 49) | 2,449 | 28.3% | 19.9% | 2,181 | 26.4% | 20.1% | +268 | +1.9pp |
| Older workers and pre-retirees (50 to 59) | 813 | 9.4% | 12.4% | 654 | 7.9% | 12.3% | +159 | +1.5pp |
| Empty nesters and retirees (60 to 69) | 476 | 5.5% | 10.9% | 333 | 4.0% | 10.1% | +143 | +1.5pp |
| Seniors (70 to 84) | 233 | 2.7% | 9.3% | 143 | 1.7% | 7.3% | +90 | +1.0pp |
| Elderly aged (85 and over) | 19 | 0.2% | 1.9% | 23 | 0.3% | 1.5% | -4 | -0.1pp |
| Total | 8,651 | 100.0% | 100.0% | 8,269 | 100.0% | 100.0% | +382 | 0.0pp |