| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 6.21 | 6.96 | 5.25 |
| 2024 | 4.65 | 5.57 | 3.86 |
| 2023 | 6.04 | 8.47 | 4.52 |
| 2022 | 6.27 | 8.65 | 4.24 |
| 2021 | 6.88 | 9.11 | 5.78 |
| 2020 | 5.35 | 7.56 | 4.03 |
| 2019 | 4.31 | 6.04 | 3.01 |
| 2018 | 4.05 | 4.99 | 3.32 |
| 2017 | 4.95 | 5.89 | 3.82 |
| 2016 | 5.18 | 6.91 | 3.18 |
| 2015 | 4.34 | 6.3 | 2.66 |
| 2014 | 2.49 | 3.9 | 1.68 |
| 2013 | 2.19 | 2.92 | 1.8 |
| 2012 | 3.03 | 5.3 | 1.75 |
| 2011 | 3.07 | 4.12 | 1.9 |
| 2010 | 2.99 | 3.99 | 2.24 |
| 2009 | 2.8 | 4.35 | 1.44 |
| 2008 | 2.84 | 6.6 | 1.15 |
| 2007 | 4.42 | 6.52 | 1.8 |
| 2006 | 1.58 | 2.39 | 1.06 |
| 2005 | 1.13 | 1.52 | 0.79 |
| 2004 | 1.99 | 2.66 | 1.46 |
| 2003 | 2.43 | 2.94 | 2.07 |
| 2002 | 3 | 3.33 | 2.01 |
| 2001 | 4.21 | 5.48 | 2.92 |
| 2000 | 3.74 | 5.3 | 2.13 |
| 1999 | 2.15 | 3.12 | 1.67 |
| 1998 | 2.18 | 2.83 | 1.73 |
| 1997 | 2.51 | 3.65 | 1.97 |