| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.87 | 2 | 1.69 |
| 2024 | 1.89 | 2.44 | 1.55 |
| 2023 | 1.68 | 2.12 | 1.46 |
| 2022 | 1.74 | 2.1 | 1.37 |
| 2021 | 2.47 | 3.45 | 1.85 |
| 2020 | 3.04 | 4.5 | 2.04 |
| 2019 | 2.23 | 2.93 | 1.34 |
| 2018 | 1.83 | 2.78 | 1.07 |
| 2017 | 3.97 | 6.97 | 2.01 |
| 2016 | 3.05 | 4.69 | 2.45 |
| 2015 | 3.97 | 6.48 | 2.44 |
| 2014 | 2.02 | 2.55 | 1.73 |
| 2013 | 1.88 | 2.73 | 1.39 |
| 2012 | 1.88 | 2.48 | 1.5 |
| 2011 | 3.03 | 4.09 | 1.75 |
| 2010 | 3.66 | 4.79 | 2.9 |
| 2009 | 4.16 | 5.77 | 2.31 |
| 2008 | 3.5 | 5.99 | 1.99 |
| 2007 | 4.91 | 7.46 | 2.02 |
| 2006 | 1.82 | 2.31 | 1.53 |
| 2005 | 2.23 | 3.05 | 1.52 |
| 2004 | 3.38 | 4.59 | 2.76 |
| 2003 | 4.23 | 5.42 | 3.16 |
| 2002 | 4.74 | 5.6 | 3.37 |
| 2001 | 6.16 | 8.13 | 3.56 |
| 2000 | 6.92 | 8.72 | 5.44 |
| 1999 | 8.07 | 13.59 | 4.91 |
| 1998 | 4.57 | 5.83 | 3.34 |
| 1997 | 4.99 | 6.99 | 4.01 |