| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.88 | 2.09 | 1.73 |
| 2024 | 1.83 | 2.38 | 1.49 |
| 2023 | 2.16 | 2.67 | 1.83 |
| 2022 | 2.41 | 3.25 | 1.97 |
| 2021 | 2.55 | 3.25 | 2.13 |
| 2020 | 3.13 | 4.05 | 2.59 |
| 2019 | 3.57 | 5.73 | 2.72 |
| 2018 | 2.43 | 4.68 | 1.64 |
| 2017 | 3.73 | 5.09 | 2.83 |
| 2016 | 5.07 | 7.76 | 4.32 |
| 2015 | 7.39 | 13.1 | 3.82 |
| 2014 | 4.06 | 6.25 | 3.52 |
| 2013 | 3.86 | 5.58 | 2.51 |
| 2012 | 4.02 | 5.65 | 2.19 |
| 2011 | 6.75 | 9.34 | 4.55 |
| 2010 | 11.72 | 33.37 | 3.5 |
| 2009 | 13.56 | 18.84 | 5.34 |
| 2008 | 6.47 | 8.38 | 2.43 |
| 2007 | 5.27 | 8.55 | 2.29 |
| 2006 | 2.5 | 3.02 | 2.03 |
| 2005 | 2.78 | 4.21 | 1.97 |
| 2004 | 5.47 | 10.11 | 3.28 |
| 2003 | 6.95 | 8.6 | 5.41 |
| 2002 | 6.72 | 8.13 | 4.71 |
| 2001 | 9.99 | 12.63 | 7.58 |
| 2000 | 7.49 | 8.61 | 5.61 |
| 1999 | 6.08 | 8.47 | 4.88 |
| 1998 | 7.2 | 11.61 | 4.64 |
| 1997 | 5.17 | 7.53 | 3.91 |