| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0 | ||
| 2024 | 0 | ||
| 2023 | 0.13 | 0.22 | 0.04 |
| 2022 | 0.21 | 0.3 | 0.1 |
| 2021 | 0.28 | 0.41 | 0.13 |
| 2020 | 0.47 | 0.56 | 0.39 |
| 2019 | 0.49 | 0.8 | 0.37 |
| 2018 | 0.81 | 1.51 | 0.48 |
| 2017 | 1.1 | 1.46 | 0.9 |
| 2016 | 1.27 | 2.21 | 1.04 |
| 2015 | 1.86 | 2.66 | 1.17 |
| 2014 | 1.38 | 1.97 | 0.96 |
| 2013 | 1.89 | 2.39 | 1.26 |
| 2012 | 1.45 | 1.9 | 0.97 |
| 2011 | 1.3 | 1.83 | 0.88 |
| 2010 | 2.16 | 4.5 | 1.39 |
| 2009 | 3.29 | 5.61 | 0.98 |
| 2008 | 2.07 | 5.44 | 0.33 |
| 2007 | 3.78 | 5.88 | 2.23 |
| 2006 | 1.96 | 2.46 | 1.63 |
| 2005 | 1.84 | 3.2 | 1.26 |
| 2004 | 2.27 | 4.2 | 1.46 |