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 Wilga, accounting for 33.3%.
Section overview
Individual income quartiles
Wilga - Persons aged 15+ (Usual residence)
This table summarises individual income quartiles for Wilga in 2021 for persons, with comparison against Boyup Brook (S) and change since 2016.
Individual income quartiles snapshot
2021 distribution by category for Wilga, with comparison markers for Boyup Brook (S).
Lowest group
2021 count
14
% of total
29.2%
Change from 2016
+3.5pp
14
29.2%
+3.5pp
Medium lowest
2021 count
16
% of total
33.3%
Change from 2016
+13.3pp
16
33.3%
+13.3pp
Medium highest
2021 count
14
% of total
29.2%
Change from 2016
-13.7pp
14
29.2%
-13.7pp
Highest group
2021 count
4
% of total
8.3%
Change from 2016
-3.1pp
4
8.3%
-3.1pp
Chart view
Individual income quartiles change
Absolute change in category counts between 2016 and 2021.
Lowest group
+5
+3.5pp
Medium lowest
+9
+13.3pp
Medium highest
-1
-13.7pp
Highest group
0
-3.1pp
Data table
Individual income quartiles for Wilga. Individual income quartiles. 2021 and 2016 counts, percentages, and change compared with Boyup Brook (S).
| Category | 2021 | 2016 | Change | |||||
|---|---|---|---|---|---|---|---|---|
| Count | % | Boyup Brook (S)% | Count | % | Boyup Brook (S)% | Count | pp | |
| Lowest group | 14 | 29.2% | 26.4% | 9 | 25.7% | 24.7% | +5 | +3.5pp |
| Medium lowest | 16 | 33.3% | 28.7% | 7 | 20.0% | 28.3% | +9 | +13.3pp |
| Medium highest | 14 | 29.2% | 24.6% | 15 | 42.9% | 25.1% | -1 | -13.7pp |
| Highest group | 4 | 8.3% | 20.3% | 4 | 11.4% | 21.9% | 0 | -3.1pp |
| Total persons aged 15+ | 48 | 100.0% | 100.0% | 35 | 100.0% | 100.0% | +13 | 0.0pp |