| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0 | ||
| 2024 | 0 | ||
| 2023 | 1.2 | 1.56 | 0.46 |
| 2022 | 1.16 | 1.71 | 0.83 |
| 2021 | 1.05 | 1.25 | 0.82 |
| 2020 | 1.31 | 1.89 | 1.01 |
| 2019 | 1.43 | 1.82 | 1.08 |
| 2018 | 1.97 | 2.2 | 1.66 |
| 2017 | 2.15 | 2.49 | 1.82 |
| 2016 | 2.57 | 4.09 | 2.17 |
| 2015 | 5.78 | 9.71 | 3.75 |
| 2014 | 2.3 | 4.67 | 1.69 |
| 2013 | 3.27 | 4.23 | 2.47 |
| 2012 | 4.24 | 5.9 | 3.07 |
| 2011 | 7.38 | 12.17 | 4.04 |
| 2010 | 7.94 | 10.25 | 5.31 |
| 2009 | 8.54 | 14.65 | 2.25 |
| 2008 | 7.31 | 13.89 | 1.65 |
| 2007 | 12.61 | 17.65 | 6.24 |
| 2006 | 4.78 | 7.76 | 1.89 |
| 2005 | 2.03 | 2.6 | 1.34 |
| 2004 | 3.06 | 4.66 | 2.08 |
| 2003 | 3.62 | 7.08 | 2.57 |
| 2002 | 14.84 | 15.95 | 13.01 |
| 2001 | 14.44 | 16.91 | 8.97 |
| 2000 | 16.69 | 25.78 | 5.55 |
| 1999 | 4.94 | 6.55 | 3.49 |
| 1998 | 4.45 | 5.4 | 3.3 |
| 1997 | 4.47 | 7.54 | 2.69 |