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 Blue Mountains (C), accounting for 19.3% (15,055 people). This share was lower than Greater Sydney (21.5%). Since 2016, the biggest change was in Seniors (70 to 84), which increased by 2,277 people and 2.7 percentage points.
Section overview
Age structure - Service age groups
Blue Mountains (C) - Total persons (Usual residence)
This table summarises service age groups for Blue Mountains (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 Blue Mountains (C), with comparison markers for Greater Sydney.
Babies and pre-schoolers (0 to 4)
2021 count
3,887
% of total
5.0%
Change from 2016
-0.5pp
3,887
5.0%
-0.5pp
Primary schoolers (5 to 11)
2021 count
6,678
% of total
8.5%
Change from 2016
-0.5pp
6,678
8.5%
-0.5pp
Secondary schoolers (12 to 17)
2021 count
6,078
% of total
7.8%
Change from 2016
+0.2pp
6,078
7.8%
+0.2pp
Tertiary education and independence (18 to 24)
2021 count
5,086
% of total
6.5%
Change from 2016
-0.5pp
5,086
6.5%
-0.5pp
Young workforce (25 to 34)
2021 count
7,127
% of total
9.1%
Change from 2016
0.0pp
7,127
9.1%
0.0pp
Parents and homebuilders (35 to 49)
2021 count
15,055
% of total
19.3%
Change from 2016
-0.5pp
15,055
19.3%
-0.5pp
Older workers and pre-retirees (50 to 59)
2021 count
10,871
% of total
13.9%
Change from 2016
-0.9pp
10,871
13.9%
-0.9pp
Empty nesters and retirees (60 to 69)
2021 count
11,333
% of total
14.5%
Change from 2016
-0.1pp
11,333
14.5%
-0.1pp
Seniors (70 to 84)
2021 count
10,251
% of total
13.1%
Change from 2016
+2.7pp
10,251
13.1%
+2.7pp
Elderly aged (85 and over)
2021 count
1,761
% of total
2.3%
Change from 2016
+0.2pp
1,761
2.3%
+0.2pp
Chart view
Age structure - Service age groups change
Absolute change in category counts between 2016 and 2021.
Babies and pre-schoolers (0 to 4)
-352
-0.5pp
Primary schoolers (5 to 11)
-255
-0.5pp
Secondary schoolers (12 to 17)
+198
+0.2pp
Tertiary education and independence (18 to 24)
-331
-0.5pp
Young workforce (25 to 34)
+143
0.0pp
Parents and homebuilders (35 to 49)
-191
-0.5pp
Older workers and pre-retirees (50 to 59)
-513
-0.9pp
Empty nesters and retirees (60 to 69)
+109
-0.1pp
Seniors (70 to 84)
+2,277
+2.7pp
Elderly aged (85 and over)
+126
+0.2pp
Data table
Service age groups for Blue Mountains (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) | 3,887 | 5.0% | 6.0% | 4,239 | 5.5% | 6.4% | -352 | -0.5pp |
| Primary schoolers (5 to 11) | 6,678 | 8.5% | 8.8% | 6,933 | 9.0% | 8.8% | -255 | -0.5pp |
| Secondary schoolers (12 to 17) | 6,078 | 7.8% | 7.1% | 5,880 | 7.6% | 6.9% | +198 | +0.2pp |
| Tertiary education and independence (18 to 24) | 5,086 | 6.5% | 8.8% | 5,417 | 7.0% | 9.6% | -331 | -0.5pp |
| Young workforce (25 to 34) | 7,127 | 9.1% | 15.5% | 6,984 | 9.1% | 16.1% | +143 | 0.0pp |
| Parents and homebuilders (35 to 49) | 15,055 | 19.3% | 21.5% | 15,246 | 19.8% | 21.1% | -191 | -0.5pp |
| Older workers and pre-retirees (50 to 59) | 10,871 | 13.9% | 12.0% | 11,384 | 14.8% | 12.2% | -513 | -0.9pp |
| Empty nesters and retirees (60 to 69) | 11,333 | 14.5% | 9.8% | 11,224 | 14.6% | 9.5% | +109 | -0.1pp |
| Seniors (70 to 84) | 10,251 | 13.1% | 8.7% | 7,974 | 10.4% | 7.5% | +2,277 | +2.7pp |
| Elderly aged (85 and over) | 1,761 | 2.3% | 2.0% | 1,635 | 2.1% | 2.0% | +126 | +0.2pp |
| Total | 78,121 | 100.0% | 100.0% | 76,904 | 100.0% | 100.0% | +1,217 | 0.0pp |