| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0 | ||
| 2024 | 0 | ||
| 2023 | 0 | ||
| 2022 | 0 | ||
| 2021 | 1.43 | 1.8 | 1.06 |
| 2020 | 0.7 | 1.39 | 0.35 |
| 2019 | 0.43 | 0.49 | 0.38 |
| 2018 | 0.46 | 0.56 | 0.38 |
| 2017 | 0.6 | 0.69 | 0.52 |
| 2016 | 0.56 | 0.66 | 0.44 |
| 2015 | 0.57 | 0.85 | 0.41 |
| 2014 | 0.36 | 0.46 | 0.31 |
| 2013 | 0.37 | 0.44 | 0.3 |
| 2012 | 0.48 | 0.76 | 0.35 |
| 2011 | 1.7 | 3.1 | 0.65 |
| 2010 | 2 | 2.54 | 1.41 |
| 2009 | 1.4 | 1.94 | 0.75 |
| 2008 | 2.34 | 4.45 | 0.48 |
| 2007 | 2.26 | 3.84 | 1.08 |
| 2006 | 1.07 | 1.32 | 0.8 |
| 2005 | 0.83 | 1.05 | 0.63 |
| 2004 | 1.03 | 1.69 | 0.68 |