| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.7 | 0.82 | 0.55 |
| 2024 | 0.55 | 1.02 | 0.31 |
| 2023 | 2.2 | 5.93 | 0.59 |
| 2022 | 5.22 | 6.76 | 2.98 |
| 2021 | 4.77 | 8.42 | 2.7 |
| 2020 | 2.43 | 4.48 | 1.83 |
| 2019 | 2.49 | 3.53 | 2.08 |
| 2018 | 3.13 | 3.95 | 2.27 |
| 2017 | 5.37 | 7.32 | 3.72 |
| 2016 | 4.18 | 6.81 | 1.96 |
| 2015 | 2.48 | 4.19 | 1.17 |
| 2014 | 1.32 | 1.56 | 1.16 |
| 2013 | 1.19 | 1.49 | 0.95 |
| 2012 | 1.13 | 1.51 | 0.91 |
| 2011 | 2.43 | 3.57 | 1.14 |
| 2010 | 3.58 | 4.73 | 2.52 |
| 2009 | 2.3 | 4.3 | 0.7 |
| 2008 | 1.73 | 3.52 | 0.55 |
| 2007 | 3.27 | 5.13 | 1.86 |
| 2006 | 2.68 | 3.74 | 2.07 |
| 2005 | 2.22 | 3.13 | 1.42 |
| 2004 | 3 | 4.88 | 1.67 |