| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 2.9 | 3.28 | 2.69 |
| 2024 | 2.79 | 3.34 | 2.23 |
| 2023 | 3.31 | 3.91 | 2.74 |
| 2022 | 3.83 | 5.87 | 3.08 |
| 2021 | 4.51 | 7.18 | 3.18 |
| 2020 | 3.8 | 4.84 | 2.98 |
| 2019 | 4.11 | 4.98 | 3.43 |
| 2018 | 4.61 | 5.49 | 3.87 |
| 2017 | 5.17 | 6.18 | 4.16 |
| 2016 | 5.95 | 7.48 | 4.92 |
| 2015 | 8.44 | 12.35 | 6.07 |
| 2014 | 8.84 | 10.4 | 6.93 |
| 2013 | 9.9 | 12.62 | 7.68 |
| 2012 | 7.61 | 9.9 | 5.97 |
| 2011 | 8.81 | 11.28 | 6.36 |
| 2010 | 10.63 | 14.37 | 7.85 |
| 2009 | 5.68 | 8.6 | 4.48 |
| 2008 | 6.97 | 11.34 | 3.93 |
| 2007 | 9.7 | 12.63 | 6.41 |
| 2006 | 3.06 | 6.83 | 1.64 |
| 2005 | 1.65 | 2.09 | 1.18 |
| 2004 | 2 | 2.63 | 1.71 |
| 2003 | 2.31 | 3.13 | 1.82 |
| 2002 | 3.53 | 3.96 | 2.73 |
| 2001 | 3.99 | 4.88 | 2.68 |
| 2000 | 5.91 | 7.91 | 4.07 |
| 1999 | 7.72 | 10.92 | 5.87 |
| 1998 | 7.36 | 9.78 | 4.08 |