Based on the data below, explain the likely relationship between real disposable income and subjective happiness.
| Year | Real Disposable Income (£) | Nominal Disposable Income (£) |
|---|---|---|
| 2010 | 24,000 | 20,000 |
| 2013 | 23,500 | 22,000 |
| 2016 | 24,000 | 24,000 |
| 2019 | 24,500 | 26,000 |
| 2022 | 24,000 | 28,500 |