| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.4 | 0.44 | 0.34 |
| 2024 | 0.44 | 0.61 | 0.31 |
| 2023 | 1.06 | 1.8 | 0.47 |
| 2022 | 2.06 | 3.54 | 1.22 |
| 2021 | 3.78 | 6.5 | 2.05 |
| 2020 | 1.17 | 2.41 | 0.77 |
| 2019 | 1.14 | 1.83 | 0.68 |
| 2018 | 8.7 | 25.9 | 1.56 |
| 2017 | 7.26 | 8.8 | 5.94 |
| 2016 | 7.83 | 9.84 | 6.77 |
| 2015 | 10.27 | 19.52 | 7.27 |
| 2014 | 4.86 | 8.78 | 3.35 |
| 2013 | 3.68 | 4.18 | 3.06 |
| 2012 | 3.95 | 5.94 | 3.15 |
| 2011 | 6.65 | 9.43 | 4.86 |
| 2010 | 7.59 | 11.51 | 5.53 |
| 2009 | 7.98 | 12.09 | 3.23 |
| 2008 | 3.32 | 5.09 | 1.96 |
| 2007 | 3.85 | 6.3 | 1.58 |
| 2006 | 0.86 | 1.57 | 0.47 |
| 2005 | 0.44 | 0.57 | 0.27 |
| 2004 | 0.73 | 1.33 | 0.43 |