| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 2.48 | 2.62 | 2.19 |
| 2024 | 2.5 | 3.16 | 2.03 |
| 2023 | 2.79 | 3.32 | 2.25 |
| 2022 | 3.27 | 4.63 | 2.32 |
| 2021 | 4.17 | 5.83 | 2.79 |
| 2020 | 2.57 | 4.44 | 1.54 |
| 2019 | 1.95 | 2.37 | 1.52 |
| 2018 | 2.13 | 2.51 | 1.81 |
| 2017 | 3.68 | 4.73 | 2.37 |
| 2016 | 4.75 | 5.79 | 4.16 |
| 2015 | 6.3 | 10.88 | 3.87 |
| 2014 | 5.83 | 12.15 | 3.67 |
| 2013 | 4.12 | 5.4 | 3.36 |
| 2012 | 3.57 | 4.78 | 2.67 |
| 2011 | 4.41 | 5.51 | 3.25 |
| 2010 | 5.61 | 10.42 | 3.31 |
| 2009 | 5.73 | 7.89 | 2.7 |
| 2008 | 4.95 | 5.49 | 2.18 |
| 2007 | 4.59 | 5.97 | 2.54 |
| 2006 | 2.4 | 3.38 | 1.67 |
| 2005 | 1.58 | 2.11 | 1.17 |
| 2004 | 2.38 | 3.69 | 1.57 |
| 2003 | 4.17 | 5.82 | 2.58 |
| 2002 | 3.93 | 4.99 | 2.14 |
| 2001 | 4.29 | 5.07 | 3.52 |
| 2000 | 3.65 | 5.16 | 2.72 |
| 1999 | 2.5 | 2.95 | 2.1 |
| 1998 | 3.9 | 5.59 | 2.38 |
| 1997 | 4.84 | 6.73 | 3.7 |