Study Figure 2, a table showing dairy farming trends in a UK region between 2015 and 2022.
| Year | Number of active dairy holdings (thousands) | Average herd size (number of cows) |
|---|---|---|
| 2015 | 10.5 | 143 |
| 2016 | 10.1 | 146 |
| 2017 | 9.8 | 149 |
| 2018 | 9.6 | 151 |
| 2019 | 9.3 | 153 |
| 2020 | 9.1 | 155 |
| 2021 | 8.8 | 158 |
| 2022 | 8.5 | 162 |
Suggest one reason for a trend shown in Figure 2.
