| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0 | ||
| 2024 | 0 | ||
| 2023 | 0.42 | 0.75 | 0.11 |
| 2022 | 1.36 | 3.67 | 0.47 |
| 2021 | 1.82 | 3.13 | 1.2 |
| 2020 | 0.73 | 1.6 | 0.34 |
| 2019 | 0.58 | 0.97 | 0.42 |
| 2018 | 1.02 | 2.09 | 0.61 |
| 2017 | 0.98 | 1.17 | 0.81 |
| 2016 | 1.62 | 2.67 | 1.11 |
| 2015 | 3.11 | 4.91 | 1.93 |
| 2014 | 1.81 | 2.43 | 1.41 |
| 2013 | 2.97 | 4.41 | 2.04 |
| 2012 | 2.38 | 2.72 | 2.07 |
| 2011 | 4.61 | 9.4 | 1.92 |
| 2010 | 9.57 | 17.25 | 7.05 |
| 2009 | 0 | ||
| 2008 | 0 | ||
| 2007 | 1.15 | 1.64 | 0.71 |
| 2006 | 0.77 | 1.06 | 0.49 |
| 2005 | 0.57 | 0.75 | 0.32 |
| 2004 | 0.92 | 1.98 | 0.51 |