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 highest income quartile held the largest share among residents aged 15 and over in Rockingham (C), accounting for 26.7%.
Section overview
Individual income quartiles
Rockingham (C) - Persons aged 15+ (Usual residence)
This table summarises individual income quartiles for Rockingham (C) in 2021 for persons, with comparison against Greater Perth and change since 2016.
Individual income quartiles snapshot
2021 distribution by category for Rockingham (C), with comparison markers for Greater Perth.
Lowest group
2021 count
25,477
% of total
25.9%
Change from 2016
+0.6pp
25,477
25.9%
+0.6pp
Medium lowest
2021 count
24,477
% of total
24.8%
Change from 2016
+1.9pp
24,477
24.8%
+1.9pp
Medium highest
2021 count
22,295
% of total
22.6%
Change from 2016
+0.5pp
22,295
22.6%
+0.5pp
Highest group
2021 count
26,274
% of total
26.7%
Change from 2016
-2.9pp
26,274
26.7%
-2.9pp
Chart view
Individual income quartiles change
Absolute change in category counts between 2016 and 2021.
Lowest group
+3,196
+0.6pp
Medium lowest
+4,308
+1.9pp
Medium highest
+2,836
+0.5pp
Highest group
+208
-2.9pp
Data table
Individual income quartiles for Rockingham (C). Individual income quartiles. 2021 and 2016 counts, percentages, and change compared with Greater Perth.
| Category | 2021 | 2016 | Change | |||||
|---|---|---|---|---|---|---|---|---|
| Count | % | Greater Perth% | Count | % | Greater Perth% | Count | pp | |
| Lowest group | 25,477 | 25.9% | 24.6% | 22,281 | 25.3% | 24.5% | +3,196 | +0.6pp |
| Medium lowest | 24,477 | 24.8% | 23.2% | 20,169 | 22.9% | 21.6% | +4,308 | +1.9pp |
| Medium highest | 22,295 | 22.6% | 23.5% | 19,459 | 22.1% | 22.7% | +2,836 | +0.5pp |
| Highest group | 26,274 | 26.7% | 28.7% | 26,066 | 29.6% | 31.2% | +208 | -2.9pp |
| Total persons aged 15+ | 98,523 | 100.0% | 100.0% | 87,975 | 100.0% | 100.0% | +10,548 | 0.0pp |