| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 2.82 | 3.18 | 2.52 |
| 2024 | 2.6 | 3.52 | 1.96 |
| 2023 | 2.72 | 4.39 | 2.03 |
| 2022 | 2.51 | 3.05 | 1.7 |
| 2021 | 1.89 | 2.7 | 1.58 |
| 2020 | 2.21 | 3.15 | 1.86 |
| 2019 | 3.03 | 4.67 | 1.93 |
| 2018 | 1.77 | 2.29 | 1.22 |
| 2017 | 3.24 | 4.45 | 2.12 |
| 2016 | 4.03 | 4.87 | 3.05 |
| 2015 | 4.75 | 8.39 | 3.06 |
| 2014 | 2.88 | 4.02 | 2.11 |
| 2013 | 2.91 | 4.46 | 2.1 |
| 2012 | 2.37 | 3.06 | 1.9 |
| 2011 | 3.18 | 3.91 | 2.22 |
| 2010 | 3.84 | 4.66 | 2.86 |
| 2009 | 3.17 | 4.47 | 1.88 |
| 2008 | 3.29 | 5.9 | 1.32 |
| 2007 | 4.15 | 6.64 | 2.65 |
| 2006 | 3.22 | 4.33 | 2.34 |
| 2005 | 1.55 | 2.7 | 0.9 |
| 2004 | 2.89 | 4.4 | 1.72 |
| 2003 | 4.47 | 5.61 | 3.01 |
| 2002 | 5.72 | 7.73 | 3.87 |
| 2001 | 8.71 | 10.3 | 7.08 |
| 2000 | 9.89 | 12.27 | 6.61 |
| 1999 | 7.69 | 11.85 | 4.28 |
| 1998 | 2.76 | 3.58 | 2.21 |
| 1997 | 2.34 | 3.17 | 1.74 |