| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2023 | 21.11 | 21.99 | 19.18 |
| 2022 | 18.48 | 25.51 | 12.98 |
| 2021 | 20.92 | 27.41 | 14.87 |
| 2020 | 21.46 | 27.32 | 15.07 |
| 2019 | 17.42 | 21.96 | 12.43 |
| 2018 | 20.18 | 35.22 | 11.85 |
| 2017 | 30.02 | 34.83 | 25.84 |
| 2016 | 28.93 | 34.37 | 25.14 |
| 2015 | 28.48 | 35.66 | 23.11 |
| 2014 | 23.46 | 31.1 | 19.94 |
| 2013 | 29.09 | 34.54 | 21.65 |
| 2012 | 22.55 | 28.1 | 18.21 |
| 2011 | 28.08 | 39.91 | 22.86 |