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 Mount Marshall (S), accounting for 28.7%.
Section overview
Individual income quartiles
Mount Marshall (S) - Persons aged 15+ (Usual residence)
This table summarises individual income quartiles for Mount Marshall (S) in 2021 for persons, with comparison against Regional WA and change since 2016.
Individual income quartiles snapshot
2021 distribution by category for Mount Marshall (S), with comparison markers for Regional WA.
Lowest group
2021 count
75
% of total
22.0%
Change from 2016
+0.3pp
75
22.0%
+0.3pp
Medium lowest
2021 count
82
% of total
24.0%
Change from 2016
-2.9pp
82
24.0%
-2.9pp
Medium highest
2021 count
86
% of total
25.2%
Change from 2016
-3.2pp
86
25.2%
-3.2pp
Highest group
2021 count
98
% of total
28.7%
Change from 2016
+5.7pp
98
28.7%
+5.7pp
Chart view
Individual income quartiles change
Absolute change in category counts between 2016 and 2021.
Lowest group
-9
+0.3pp
Medium lowest
-22
-2.9pp
Medium highest
-24
-3.2pp
Highest group
+9
+5.7pp
Data table
Individual income quartiles for Mount Marshall (S). Individual income quartiles. 2021 and 2016 counts, percentages, and change compared with Regional WA.
| Category | 2021 | 2016 | Change | |||||
|---|---|---|---|---|---|---|---|---|
| Count | % | Regional WA% | Count | % | Regional WA% | Count | pp | |
| Lowest group | 75 | 22.0% | 24.1% | 84 | 21.7% | 22.1% | -9 | +0.3pp |
| Medium lowest | 82 | 24.0% | 25.7% | 104 | 26.9% | 24.3% | -22 | -2.9pp |
| Medium highest | 86 | 25.2% | 23.0% | 110 | 28.4% | 22.8% | -24 | -3.2pp |
| Highest group | 98 | 28.7% | 27.3% | 89 | 23.0% | 30.7% | +9 | +5.7pp |
| Total persons aged 15+ | 341 | 100.0% | 100.0% | 387 | 100.0% | 100.0% | -46 | 0.0pp |