| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 2.32 | 2.41 | 2.2 |
| 2024 | 2.58 | 3.19 | 2.04 |
| 2023 | 3.23 | 3.78 | 2.76 |
| 2022 | 2.99 | 3.86 | 2.52 |
| 2021 | 4.23 | 5.1 | 3.61 |
| 2020 | 5.38 | 6.89 | 4.13 |
| 2019 | 6.3 | 8.07 | 4.67 |
| 2018 | 8.73 | 11.42 | 5.06 |
| 2017 | 7.97 | 9.62 | 6.82 |
| 2016 | 11.07 | 13.34 | 8.15 |
| 2015 | 11.42 | 17.02 | 7.74 |
| 2014 | 6.85 | 10.45 | 5.13 |
| 2013 | 6.45 | 8.66 | 3.53 |
| 2012 | 3.19 | 3.76 | 2.76 |
| 2011 | 4.16 | 5.61 | 3.04 |
| 2010 | 4.38 | 6.52 | 3.29 |
| 2009 | 3.95 | 4.77 | 3.23 |
| 2008 | 3.49 | 4.58 | 2.4 |
| 2007 | 3.84 | 5.76 | 2.55 |
| 2006 | 1.48 | 2.5 | 0.88 |
| 2005 | 0.93 | 1.14 | 0.76 |
| 2004 | 1.43 | 1.89 | 1.06 |
| 2003 | 1.8 | 2.48 | 1.33 |
| 2002 | 2.22 | 2.8 | 1.44 |
| 2001 | 2.5 | 3.08 | 1.81 |
| 2000 | 2.97 | 3.68 | 1.83 |
| 1999 | 2.67 | 4.53 | 1.82 |
| 1998 | 3.31 | 4.16 | 2.46 |
| 1997 | 5.39 | 8.2 | 3.55 |