Income
Individual income quartiles
About this topic
Individual income quartiles group people aged 15 years and over into four evenly sized income ranges so the distribution of personal income can be compared objectively across areas and over time. The quartile method focuses on relative position in the income distribution rather than raw dollar brackets.
This topic is useful because direct income amounts are affected by inflation and wider economic change. Quartiles provide a clearer way to compare whether an area is becoming relatively lower, middle, or higher income over time.
Interpretation notes
- This is a derived distribution of personal income for people aged 15 years and over, with each quartile representing a quarter of the income distribution.
- Quartiles show relative position rather than fixed dollar brackets, which makes them more robust for comparisons over time.
Key insight
In 2021, the medium-low income quartile held the largest share among residents aged 15 and over in Tumby Bay (DC), accounting for 35.1%.
Section overview
Individual income quartiles
Tumby Bay (DC) - Persons aged 15+ (Usual residence)
This table summarises individual income quartiles for Tumby Bay (DC) in 2021 for persons, with comparison against Regional SA and change since 2016.
Individual income quartiles snapshot
2021 distribution by category for Tumby Bay (DC), with comparison markers for Regional SA.
Lowest group
2021 count
520
% of total
24.1%
Change from 2016
+1.4pp
520
24.1%
+1.4pp
Medium lowest
2021 count
757
% of total
35.1%
Change from 2016
+2.8pp
757
35.1%
+2.8pp
Medium highest
2021 count
524
% of total
24.3%
Change from 2016
-2.4pp
524
24.3%
-2.4pp
Highest group
2021 count
353
% of total
16.4%
Change from 2016
-2.0pp
353
16.4%
-2.0pp
Chart view
Individual income quartiles change
Absolute change in category counts between 2016 and 2021.
Lowest group
+78
+1.4pp
Medium lowest
+128
+2.8pp
Medium highest
+4
-2.4pp
Highest group
-6
-2.0pp
Data table
Individual income quartiles for Tumby Bay (DC). Individual income quartiles. 2021 and 2016 counts, percentages, and change compared with Regional SA.
| Category | 2021 | 2016 | Change | |||||
|---|---|---|---|---|---|---|---|---|
| Count | % | Regional SA% | Count | % | Regional SA% | Count | pp | |
| Lowest group | 520 | 24.1% | 25.7% | 442 | 22.7% | 22.8% | +78 | +1.4pp |
| Medium lowest | 757 | 35.1% | 33.6% | 629 | 32.3% | 33.6% | +128 | +2.8pp |
| Medium highest | 524 | 24.3% | 24.6% | 520 | 26.7% | 25.8% | +4 | -2.4pp |
| Highest group | 353 | 16.4% | 16.2% | 359 | 18.4% | 17.8% | -6 | -2.0pp |
| Total persons aged 15+ | 2,154 | 100.0% | 100.0% | 1,950 | 100.0% | 100.0% | +204 | 0.0pp |