| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0 | ||
| 2024 | 0.51 | 0.75 | 0.37 |
| 2023 | 0.61 | 0.8 | 0.48 |
| 2022 | 0.55 | 0.72 | 0.43 |
| 2021 | 0.62 | 0.87 | 0.52 |
| 2020 | 0.67 | 0.78 | 0.54 |
| 2019 | 0.79 | 1.04 | 0.57 |
| 2018 | 0.94 | 1.57 | 0.57 |
| 2017 | 2.02 | 3 | 1.38 |
| 2016 | 1.71 | 1.88 | 1.41 |
| 2015 | 2 | 2.84 | 1.42 |
| 2014 | 1 | 1.72 | 0.51 |
| 2013 | 0.57 | 0.65 | 0.5 |
| 2012 | 0.63 | 0.73 | 0.57 |
| 2011 | 0.84 | 1.09 | 0.62 |
| 2010 | 1.12 | 1.46 | 0.82 |
| 2009 | 1.3 | 1.59 | 0.99 |
| 2008 | 1.55 | 3.8 | 0.74 |
| 2007 | 3.2 | 5.16 | 0.57 |
| 2006 | 0.5 | 0.62 | 0.4 |
| 2005 | 0.56 | 0.84 | 0.39 |
| 2004 | 2.43 | 9.98 | 0.75 |