| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 2.5 | 3.1 | 1.98 |
| 2024 | 1.96 | 3.34 | 1.16 |
| 2023 | 3.17 | 3.61 | 2.69 |
| 2022 | 3.97 | 6.06 | 2.9 |
| 2021 | 4.16 | 6.47 | 2.28 |
| 2020 | 3.06 | 5.58 | 2.21 |
| 2019 | 2.76 | 4.84 | 1.98 |
| 2018 | 4.52 | 7.17 | 1.83 |
| 2017 | 7.86 | 9.38 | 6.93 |
| 2016 | 7.31 | 8.78 | 5.06 |
| 2015 | 7.71 | 12.36 | 3.77 |
| 2014 | 6.11 | 7.83 | 4.87 |
| 2013 | 3.48 | 5.76 | 2.19 |
| 2012 | 2.39 | 3.12 | 1.88 |
| 2011 | 4.99 | 8.61 | 3.03 |
| 2010 | 4.11 | 4.58 | 2.95 |