| Year (December) | Budget deficit (£ billion) |
|---|---|
| 2018 | 156.4 |
| 2019 | 124.8 |
| 2020 | 98.5 |
| 2021 | 74.1 |
| 2022 | 59.3 |
| 2023 | 48.2 |
Using the table above, calculate the percentage decrease in Valeska's budget deficit between December 2018 and December 2023. You are advised to show your working.