| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0 | ||
| 2024 | 0 | ||
| 2023 | 0 | ||
| 2022 | 0 | ||
| 2021 | 0 | ||
| 2020 | 0.54 | 1.53 | 0.22 |
| 2019 | 1.31 | 1.87 | 1.05 |
| 2018 | 2.51 | 3.72 | 0.83 |
| 2017 | 4.32 | 5.6 | 3.56 |
| 2016 | 3.89 | 6.21 | 3.04 |
| 2015 | 5.48 | 7.57 | 3.31 |
| 2014 | 2.84 | 4.17 | 2.29 |
| 2013 | 2.25 | 2.86 | 1.68 |
| 2012 | 3.05 | 4.17 | 2.29 |
| 2011 | 3.53 | 4.37 | 2.71 |
| 2010 | 3.74 | 4.92 | 3.07 |
| 2009 | 2.03 | 3.94 | 0.85 |
| 2008 | 2.11 | 3.8 | 0.7 |
| 2007 | 2.83 | 4.06 | 1.47 |
| 2006 | 1.22 | 1.65 | 0.96 |
| 2005 | 1 | 1.42 | 0.74 |
| 2004 | 1.75 | 3.95 | 0.81 |