| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.73 | 1.99 | 1.56 |
| 2024 | 1.75 | 2.15 | 1.22 |
| 2023 | 2.3 | 3.1 | 1.84 |
| 2022 | 3.34 | 4.66 | 2.58 |
| 2021 | 3.83 | 7.11 | 2.34 |
| 2020 | 2.68 | 3.23 | 1.93 |
| 2019 | 2.56 | 3.3 | 2.14 |
| 2018 | 3.47 | 5.52 | 2.41 |
| 2017 | 6.59 | 8.59 | 4.6 |
| 2016 | 6.89 | 8.66 | 4.61 |
| 2015 | 5.24 | 8.24 | 2.76 |
| 2014 | 2.97 | 4.45 | 2.15 |
| 2013 | 2.75 | 3.31 | 2.27 |
| 2012 | 4 | 6.07 | 2.4 |
| 2011 | 6.27 | 14.84 | 3.46 |
| 2010 | 5.89 | 6.94 | 4.52 |
| 2009 | 4.2 | 6.26 | 2.49 |
| 2008 | 2.82 | 5.53 | 1.49 |