| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 3.79 | 4.01 | 3.53 |
| 2024 | 3.62 | 4.44 | 2.98 |
| 2023 | 3 | 4.02 | 2.24 |
| 2022 | 2.18 | 2.64 | 1.77 |
| 2021 | 1.84 | 2.44 | 1.66 |
| 2020 | 1.98 | 2.39 | 1.67 |
| 2019 | 2.09 | 2.57 | 1.76 |
| 2018 | 2.4 | 2.9 | 1.97 |
| 2017 | 3.58 | 4.35 | 2.69 |
| 2016 | 3.87 | 4.6 | 2.99 |
| 2015 | 5.14 | 7.08 | 3.11 |
| 2014 | 2.66 | 3.42 | 2.21 |
| 2013 | 3 | 4 | 2.39 |
| 2012 | 3.88 | 4.69 | 2.81 |
| 2011 | 5.72 | 10.56 | 3.98 |
| 2010 | 9.27 | 11.7 | 7.41 |
| 2009 | 4.99 | 7.9 | 3.71 |
| 2008 | 4.15 | 7.09 | 2.21 |
| 2007 | 5.59 | 7.58 | 2.72 |
| 2006 | 1.89 | 2.77 | 1.28 |
| 2005 | 1.15 | 1.48 | 0.87 |
| 2004 | 1.98 | 2.87 | 1.49 |
| 2003 | 2.94 | 3.49 | 2.28 |
| 2002 | 3.96 | 4.37 | 3.52 |
| 2001 | 4.52 | 5.28 | 3.16 |
| 2000 | 4.29 | 4.91 | 3.47 |
| 1999 | 6.36 | 9.43 | 4.87 |
| 1998 | 5.6 | 7.47 | 3.46 |
| 1997 | 4.86 | 7.66 | 3.56 |