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 Willoughby (C), accounting for 24.5% (18,556 people). This share was higher than Greater Sydney (21.5%). Since 2016, the biggest change was in Young workforce (25 to 34), which decreased by 1,949 people and 2.8 percentage points.
Section overview
Age structure - Service age groups
Willoughby (C) - Total persons (Usual residence)
This table summarises service age groups for Willoughby (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 Willoughby (C), with comparison markers for Greater Sydney.
Babies and pre-schoolers (0 to 4)
Primary schoolers (5 to 11)
Secondary schoolers (12 to 17)
Tertiary education and independence (18 to 24)
Young workforce (25 to 34)
Parents and homebuilders (35 to 49)
Older workers and pre-retirees (50 to 59)
Empty nesters and retirees (60 to 69)
Seniors (70 to 84)
Elderly aged (85 and over)
Chart view
Age structure - Service age groups change
Absolute change in category counts between 2016 and 2021.
Babies and pre-schoolers (0 to 4)
-947
-1.4pp
Primary schoolers (5 to 11)
+163
+0.1pp
Secondary schoolers (12 to 17)
+965
+1.2pp
Tertiary education and independence (18 to 24)
-625
-0.9pp
Young workforce (25 to 34)
-1,949
-2.8pp
Parents and homebuilders (35 to 49)
+819
+0.6pp
Older workers and pre-retirees (50 to 59)
+736
+0.7pp
Empty nesters and retirees (60 to 69)
+381
+0.4pp
Seniors (70 to 84)
+1,517
+1.9pp
Elderly aged (85 and over)
+226
+0.3pp
Data table
Service age groups for Willoughby (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) | 3,954 | 5.2% | 6.0% | 4,901 | 6.6% | 6.4% | -947 | -1.4pp |
| Primary schoolers (5 to 11) | 7,314 | 9.7% | 8.8% | 7,151 | 9.6% | 8.8% | +163 | +0.1pp |
| Secondary schoolers (12 to 17) | 5,734 | 7.6% | 7.1% | 4,769 | 6.4% | 6.9% | +965 | +1.2pp |
| Tertiary education and independence (18 to 24) | 5,424 | 7.2% | 8.8% | 6,049 | 8.1% | 9.6% | -625 | -0.9pp |
| Young workforce (25 to 34) | 9,373 | 12.4% | 15.5% | 11,322 | 15.2% | 16.1% | -1,949 | -2.8pp |
| Parents and homebuilders (35 to 49) | 18,556 | 24.5% | 21.5% | 17,737 | 23.9% | 21.1% | +819 | +0.6pp |
| Older workers and pre-retirees (50 to 59) | 9,408 | 12.4% | 12.0% | 8,672 | 11.7% | 12.2% | +736 | +0.7pp |
| Empty nesters and retirees (60 to 69) | 7,152 | 9.5% | 9.8% | 6,771 | 9.1% | 9.5% | +381 | +0.4pp |
| Seniors (70 to 84) | 6,719 | 8.9% | 8.7% | 5,202 | 7.0% | 7.5% | +1,517 | +1.9pp |
| Elderly aged (85 and over) | 1,959 | 2.6% | 2.0% | 1,733 | 2.3% | 2.0% | +226 | +0.3pp |
| Total | 75,613 | 100.0% | 100.0% | 74,302 | 100.0% | 100.0% | +1,311 | 0.0pp |