| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.79 | 2.08 | 1.55 |
| 2024 | 1.76 | 2.74 | 1.22 |
| 2023 | 3.21 | 4.26 | 2.49 |
| 2022 | 3.38 | 5.08 | 2.37 |
| 2021 | 4.36 | 7.07 | 2.51 |
| 2020 | 2.28 | 2.69 | 1.52 |
| 2019 | 2.01 | 3.39 | 0.8 |
| 2018 | 1.58 | 3.53 | 0.93 |
| 2017 | 2.38 | 2.97 | 1.9 |
| 2016 | 2.45 | 3.39 | 1.95 |
| 2015 | 8.87 | 18.21 | 3.02 |
| 2014 | 7.59 | 10.27 | 5.79 |
| 2013 | 5.61 | 8.67 | 3.82 |
| 2012 | 4.22 | 5.92 | 2.42 |
| 2011 | 4.17 | 5.45 | 2.76 |
| 2010 | 4.52 | 6.5 | 3.38 |
| 2009 | 3.72 | 4.91 | 2.63 |
| 2008 | 3.93 | 6.43 | 1.95 |
| 2007 | 4.68 | 7.4 | 3.1 |
| 2006 | 2.54 | 4.02 | 1.63 |
| 2005 | 1.66 | 2.29 | 1.27 |
| 2004 | 2.83 | 4.05 | 2.07 |
| 2003 | 3.9 | 4.84 | 2.91 |
| 2002 | 4.84 | 6.02 | 2.54 |
| 2001 | 5.09 | 6.2 | 3.49 |
| 2000 | 5.31 | 6.43 | 4.63 |
| 1999 | 6.45 | 12.72 | 5.04 |
| 1998 | 6.48 | 7.89 | 4.3 |
| 1997 | 5.28 | 7.73 | 3.46 |