| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0 | ||
| 2024 | 0 | ||
| 2023 | 0 | ||
| 2022 | 0 | ||
| 2021 | 3.37 | 3.47 | 3.28 |
| 2020 | 3.24 | 4.04 | 2.75 |
| 2019 | 3.67 | 4.84 | 3.18 |
| 2018 | 4.35 | 5.6 | 3.48 |
| 2017 | 6.03 | 7.36 | 5.54 |
| 2016 | 6.38 | 7.8 | 5.53 |
| 2015 | 9.16 | 12.7 | 7.2 |
| 2014 | 4.78 | 9.66 | 1.89 |
| 2013 | 2.13 | 2.55 | 1.79 |
| 2012 | 1.7 | 2.65 | 1.28 |
| 2011 | 2.36 | 3.32 | 1.44 |
| 2010 | 3.98 | 5.56 | 2.87 |
| 2009 | 3.27 | 5.03 | 2.07 |
| 2008 | 3.82 | 6.25 | 1.97 |
| 2007 | 5.41 | 7.21 | 2.83 |
| 2006 | 2.61 | 3.44 | 2.29 |
| 2005 | 3.6 | 4.68 | 2.43 |
| 2004 | 4.03 | 6.03 | 2.66 |