| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 3.2 | 3.57 | 3.03 |
| 2024 | 3.58 | 4.83 | 2.91 |
| 2023 | 5.02 | 7.18 | 3.85 |
| 2022 | 5.84 | 7.81 | 4.17 |
| 2021 | 5.18 | 6.15 | 4.47 |
| 2020 | 7.16 | 12.15 | 5.53 |
| 2019 | 6.74 | 11.62 | 3.75 |
| 2018 | 4.82 | 6.13 | 3.6 |
| 2017 | 8.14 | 12.5 | 5.58 |
| 2016 | 9.26 | 11.3 | 7.4 |
| 2015 | 7.54 | 12.37 | 5.48 |
| 2014 | 5.78 | 7.91 | 4.61 |
| 2013 | 6.48 | 10.99 | 4.25 |
| 2012 | 14.07 | 26.1 | 5.27 |
| 2011 | 31.4 | 40.72 | 22.11 |
| 2010 | 26.09 | 44.49 | 12.83 |
| 2009 | 18 | 29.94 | 5.25 |
| 2008 | 6.32 | 10.53 | 3.19 |