| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.94 | 2.03 | 1.84 |
| 2024 | 1.97 | 2.58 | 1.57 |
| 2023 | 1.8 | 2.25 | 1.49 |
| 2022 | 2.1 | 3.67 | 1.23 |
| 2021 | 1.29 | 1.41 | 1.21 |
| 2020 | 1.55 | 1.86 | 1.36 |
| 2019 | 1.66 | 1.99 | 1.47 |
| 2018 | 2.5 | 3.02 | 1.61 |
| 2017 | 2.64 | 2.97 | 2.41 |
| 2016 | 2.24 | 2.65 | 1.86 |
| 2015 | 2.49 | 3.38 | 1.83 |
| 2014 | 2.06 | 2.59 | 1.71 |
| 2013 | 2.71 | 3.54 | 2.23 |
| 2012 | 2.44 | 3.23 | 1.73 |
| 2011 | 3.38 | 4.37 | 2.03 |
| 2010 | 4.38 | 5.16 | 3.62 |
| 2009 | 3.84 | 4.29 | 3.46 |
| 2008 | 5.2 | 7.85 | 2.91 |
| 2007 | 4.55 | 7.47 | 1.89 |
| 2006 | 1.62 | 2.04 | 1.23 |
| 2005 | 1.36 | 1.72 | 1.09 |
| 2004 | 4.23 | 7.93 | 1.2 |
| 2003 | 6.25 | 7.6 | 4.77 |
| 2002 | 5.57 | 7.67 | 3.8 |
| 2001 | 7.42 | 8.11 | 6.63 |
| 2000 | 5.26 | 7.11 | 3.4 |
| 1999 | 4.19 | 5.27 | 3.19 |
| 1998 | 4.07 | 4.91 | 2.95 |