Population
Five year age groups
Five year age groups show the population in standard five-year cohorts from early childhood through older age. Because each band covers the same span of years, the topic gives a clear and comparable view of an area's age structure.
Related topics
About this topic
Five year age groups show the population in standard five-year cohorts from early childhood through older age. Because each band covers the same span of years, the topic gives a clear and comparable view of an area's age structure.
This topic is useful for identifying growth or decline in specific cohorts and for comparing age patterns across places and over time. For service planning, it is often read together with service age groups, household types, and dwelling types.
Interpretation notes
- Age is reported as at Census night, so the counts are a snapshot of the resident age structure at that point in time.
- Because each band covers the same five-year span, this topic is best for exact cohort comparison rather than service-planning life stages.
Key insight
In 2021, 30 to 34 year olds was the largest age group among residents in St Marys (SA), accounting for 10.7% (323 people). This share was higher than Mitcham (C) (5.4%). Since 2016, the biggest change was in 25 to 29 year olds, which increased by 80 people and 2 percentage points.
Section overview
Age structure - Five year age groups
St Marys (SA) - Total persons (Usual residence)
This table summarises five year age groups for St Marys (SA) in 2021 for persons, with comparison against Mitcham (C) and change since 2016.
Age structure - Five year age groups snapshot
2021 distribution by category for St Marys (SA), with comparison markers for Mitcham (C).
0 to 4
5 to 9
10 to 14
15 to 19
20 to 24
25 to 29
30 to 34
35 to 39
40 to 44
45 to 49
50 to 54
55 to 59
60 to 64
65 to 69
70 to 74
75 to 79
80 to 84
85 and over
Chart view
Age structure - Five year age groups change
Absolute change in category counts between 2016 and 2021.
0 to 4
+4
-0.5pp
5 to 9
-9
-0.9pp
10 to 14
-2
-0.5pp
15 to 19
+18
+0.1pp
20 to 24
-14
-1.2pp
25 to 29
+80
+2.0pp
30 to 34
+18
-0.4pp
35 to 39
+59
+1.3pp
40 to 44
+30
+0.4pp
45 to 49
-16
-1.1pp
50 to 54
-8
-0.8pp
55 to 59
+27
+0.4pp
60 to 64
+53
+1.5pp
65 to 69
-10
-0.6pp
70 to 74
+3
-0.2pp
75 to 79
0
-0.2pp
80 to 84
+16
+0.4pp
85 and over
0
-0.2pp
Data table
Five year age groups for St Marys (SA). Age structure - Five year age groups. 2021 and 2016 counts, percentages, and change compared with Mitcham (C).
| Category | 2021 | 2016 | Change | |||||
|---|---|---|---|---|---|---|---|---|
| Count | % | Mitcham (C)% | Count | % | Mitcham (C)% | Count | pp | |
| 0 to 4 | 199 | 6.6% | 4.9% | 195 | 7.1% | 5.3% | +4 | -0.5pp |
| 5 to 9 | 161 | 5.3% | 6.0% | 170 | 6.2% | 6.2% | -9 | -0.9pp |
| 10 to 14 | 138 | 4.6% | 6.4% | 140 | 5.1% | 6.1% | -2 | -0.5pp |
| 15 to 19 | 155 | 5.1% | 6.4% | 137 | 5.0% | 6.6% | +18 | +0.1pp |
| 20 to 24 | 200 | 6.6% | 6.0% | 214 | 7.8% | 6.4% | -14 | -1.2pp |
| 25 to 29 | 321 | 10.7% | 5.1% | 241 | 8.7% | 5.1% | +80 | +2.0pp |
| 30 to 34 | 323 | 10.7% | 5.4% | 305 | 11.1% | 5.6% | +18 | -0.4pp |
| 35 to 39 | 276 | 9.2% | 6.2% | 217 | 7.9% | 6.0% | +59 | +1.3pp |
| 40 to 44 | 220 | 7.3% | 6.6% | 190 | 6.9% | 6.9% | +30 | +0.4pp |
| 45 to 49 | 160 | 5.3% | 7.1% | 176 | 6.4% | 7.1% | -16 | -1.1pp |
| 50 to 54 | 152 | 5.0% | 6.7% | 160 | 5.8% | 6.7% | -8 | -0.8pp |
| 55 to 59 | 167 | 5.5% | 6.2% | 140 | 5.1% | 6.7% | +27 | +0.4pp |
| 60 to 64 | 153 | 5.1% | 6.1% | 100 | 3.6% | 5.8% | +53 | +1.5pp |
| 65 to 69 | 92 | 3.1% | 5.4% | 102 | 3.7% | 5.7% | -10 | -0.6pp |
| 70 to 74 | 104 | 3.5% | 5.4% | 101 | 3.7% | 4.6% | +3 | -0.2pp |
| 75 to 79 | 77 | 2.6% | 4.1% | 77 | 2.8% | 3.4% | 0 | -0.2pp |
| 80 to 84 | 67 | 2.2% | 2.8% | 51 | 1.8% | 2.5% | +16 | +0.4pp |
| 85 and over | 57 | 1.9% | 3.3% | 57 | 2.1% | 3.4% | 0 | -0.2pp |
| Total | 3,010 | 100.0% | 100.0% | 2,759 | 100.0% | 100.0% | +251 | 0.0pp |