| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 2.17 | 2.31 | 2.04 |
| 2024 | 2.75 | 3.98 | 1.99 |
| 2023 | 2.96 | 3.95 | 2.36 |
| 2022 | 2.32 | 2.92 | 1.96 |
| 2021 | 3.18 | 4 | 2.66 |
| 2020 | 3.48 | 4.48 | 2.78 |
| 2019 | 3.72 | 4.44 | 3.18 |
| 2018 | 3.42 | 4.43 | 2.55 |
| 2017 | 4.23 | 4.8 | 3.78 |
| 2016 | 4.64 | 5.4 | 3.97 |
| 2015 | 5.85 | 8.2 | 4.75 |
| 2014 | 4.09 | 5.07 | 3.18 |
| 2013 | 4 | 5.25 | 2.85 |
| 2012 | 4.93 | 7.03 | 3.69 |
| 2011 | 6.97 | 9.1 | 5.42 |
| 2010 | 8.85 | 12.38 | 6.43 |
| 2009 | 5.73 | 8.25 | 2.34 |
| 2008 | 5.14 | 10.79 | 1.79 |
| 2007 | 7.87 | 11.35 | 4.43 |
| 2006 | 3.08 | 4.69 | 2.41 |
| 2005 | 1.82 | 3.06 | 1.21 |
| 2004 | 2.43 | 3.83 | 1.71 |
| 2003 | 3.6 | 4.47 | 3.05 |
| 2002 | 4.82 | 5.69 | 2.98 |
| 2001 | 5.89 | 7.88 | 4.23 |
| 2000 | 5.35 | 6.64 | 3.64 |
| 1999 | 3.11 | 3.89 | 2.28 |
| 1998 | 2.25 | 2.85 | 1.77 |
| 1997 | 2.46 | 3.89 | 1.81 |