Population
Five year age groups
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.
Related topics
Key insight
In 2021, 25 to 29 year olds was the largest age group among residents in Seaford Heights, accounting for 18.9% (204 people). This share was higher than Onkaparinga (C) (6%). Since 2016, the biggest change was in 55 to 59 year olds, which decreased by 242 people and 6.8 percentage points.
Section overview
Age structure - Five year age groups
Seaford Heights - Total persons (Usual residence)
This table summarises five year age groups for Seaford Heights in 2021 for persons, with comparison against Onkaparinga (C) and change since 2016.
Age structure - Five year age groups snapshot
2021 distribution by category for Seaford Heights, with comparison markers for Onkaparinga (C).
0 to 4
2021 count
113
% of total
10.5%
Change from 2016
+5.7pp
113
10.5%
+5.7pp
5 to 9
2021 count
90
% of total
8.3%
Change from 2016
+4.1pp
90
8.3%
+4.1pp
10 to 14
2021 count
53
% of total
4.9%
Change from 2016
+0.4pp
53
4.9%
+0.4pp
15 to 19
2021 count
52
% of total
4.8%
Change from 2016
-0.8pp
52
4.8%
-0.8pp
20 to 24
2021 count
76
% of total
7.0%
Change from 2016
+2.4pp
76
7.0%
+2.4pp
25 to 29
2021 count
204
% of total
18.9%
Change from 2016
+13.6pp
204
18.9%
+13.6pp
30 to 34
2021 count
143
% of total
13.3%
Change from 2016
+8.3pp
143
13.3%
+8.3pp
35 to 39
2021 count
92
% of total
8.5%
Change from 2016
+2.1pp
92
8.5%
+2.1pp
40 to 44
2021 count
53
% of total
4.9%
Change from 2016
-2.3pp
53
4.9%
-2.3pp
45 to 49
2021 count
55
% of total
5.1%
Change from 2016
-4.4pp
55
5.1%
-4.4pp
50 to 54
2021 count
54
% of total
5.0%
Change from 2016
-4.8pp
54
5.0%
-4.8pp
55 to 59
2021 count
33
% of total
3.1%
Change from 2016
-6.8pp
33
3.1%
-6.8pp
60 to 64
2021 count
19
% of total
1.8%
Change from 2016
-5.8pp
19
1.8%
-5.8pp
65 to 69
2021 count
28
% of total
2.6%
Change from 2016
-2.8pp
28
2.6%
-2.8pp
70 to 74
2021 count
6
% of total
0.6%
Change from 2016
-3.4pp
6
0.6%
-3.4pp
75 to 79
2021 count
7
% of total
0.6%
Change from 2016
-2.0pp
7
0.6%
-2.0pp
80 to 84
2021 count
4
% of total
0.4%
Change from 2016
-1.7pp
4
0.4%
-1.7pp
85 and over
2021 count
5
% of total
0.5%
Change from 2016
-2.1pp
5
0.5%
-2.1pp
Chart view
Age structure - Five year age groups change
Absolute change in category counts between 2016 and 2021.
0 to 4
-21
+5.7pp
5 to 9
-25
+4.1pp
10 to 14
-72
+0.4pp
15 to 19
-103
-0.8pp
20 to 24
-52
+2.4pp
25 to 29
+58
+13.6pp
30 to 34
+4
+8.3pp
35 to 39
-86
+2.1pp
40 to 44
-145
-2.3pp
45 to 49
-207
-4.4pp
50 to 54
-216
-4.8pp
55 to 59
-242
-6.8pp
60 to 64
-192
-5.8pp
65 to 69
-122
-2.8pp
70 to 74
-105
-3.4pp
75 to 79
-64
-2.0pp
80 to 84
-55
-1.7pp
85 and over
-68
-2.1pp
Data table
Five year age groups for Seaford Heights. Age structure - Five year age groups. 2021 and 2016 counts, percentages, and change compared with Onkaparinga (C).
| Category | 2021 | 2016 | Change | |||||
|---|---|---|---|---|---|---|---|---|
| Count | % | Onkaparinga (C)% | Count | % | Onkaparinga (C)% | Count | pp | |
| 0 to 4 | 113 | 10.5% | 5.4% | 134 | 4.8% | 6.2% | -21 | +5.7pp |
| 5 to 9 | 90 | 8.3% | 6.2% | 115 | 4.2% | 6.4% | -25 | +4.1pp |
| 10 to 14 | 53 | 4.9% | 6.2% | 125 | 4.5% | 6.1% | -72 | +0.4pp |
| 15 to 19 | 52 | 4.8% | 5.8% | 155 | 5.6% | 6.2% | -103 | -0.8pp |
| 20 to 24 | 76 | 7.0% | 5.6% | 128 | 4.6% | 6.0% | -52 | +2.4pp |
| 25 to 29 | 204 | 18.9% | 6.0% | 146 | 5.3% | 5.9% | +58 | +13.6pp |
| 30 to 34 | 143 | 13.3% | 6.3% | 139 | 5.0% | 6.5% | +4 | +8.3pp |
| 35 to 39 | 92 | 8.5% | 6.7% | 178 | 6.4% | 6.3% | -86 | +2.1pp |
| 40 to 44 | 53 | 4.9% | 6.1% | 198 | 7.2% | 6.6% | -145 | -2.3pp |
| 45 to 49 | 55 | 5.1% | 6.4% | 262 | 9.5% | 6.9% | -207 | -4.4pp |
| 50 to 54 | 54 | 5.0% | 6.6% | 270 | 9.8% | 6.7% | -216 | -4.8pp |
| 55 to 59 | 33 | 3.1% | 6.5% | 275 | 9.9% | 6.6% | -242 | -6.8pp |
| 60 to 64 | 19 | 1.8% | 6.3% | 211 | 7.6% | 6.3% | -192 | -5.8pp |
| 65 to 69 | 28 | 2.6% | 5.9% | 150 | 5.4% | 6.1% | -122 | -2.8pp |
| 70 to 74 | 6 | 0.6% | 5.7% | 111 | 4.0% | 4.3% | -105 | -3.4pp |
| 75 to 79 | 7 | 0.6% | 3.8% | 71 | 2.6% | 2.8% | -64 | -2.0pp |
| 80 to 84 | 4 | 0.4% | 2.3% | 59 | 2.1% | 2.0% | -55 | -1.7pp |
| 85 and over | 5 | 0.5% | 2.2% | 73 | 2.6% | 2.1% | -68 | -2.1pp |
| Total | 1,079 | 100.0% | 100.0% | 2,764 | 100.0% | 100.0% | -1,685 | 0.0pp |