| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.11 | 1.77 | 0.86 |
| 2024 | 0.86 | 1.2 | 0.65 |
| 2023 | 1.12 | 1.34 | 0.9 |
| 2022 | 1.33 | 2.1 | 0.97 |
| 2021 | 0.62 | 1.26 | 0.52 |
| 2020 | 0.78 | 1.07 | 0.63 |
| 2019 | 0.81 | 1.1 | 0.67 |
| 2018 | 0.94 | 1.31 | 0.65 |
| 2017 | 1.4 | 1.7 | 1.08 |
| 2016 | 1.73 | 2.13 | 1.46 |
| 2015 | 3.19 | 4.82 | 1.94 |
| 2014 | 2.29 | 3.59 | 1.7 |
| 2013 | 7.95 | 23.62 | 1.86 |
| 2012 | 13.57 | 19.84 | 9.02 |
| 2011 | 14.4 | 19.03 | 10.43 |
| 2010 | 15.72 | 20.46 | 9.89 |
| 2009 | 8.59 | 14.08 | 4 |
| 2008 | 8.39 | 17.04 | 3.01 |
| 2007 | 13.97 | 22.33 | 9.68 |
| 2006 | 8.56 | 16.41 | 1.44 |
| 2005 | 1.72 | 2.31 | 1.24 |
| 2004 | 2.38 | 3.58 | 1.67 |
| 2003 | 2.51 | 3.09 | 1.77 |
| 2002 | 3.53 | 4.01 | 2.67 |
| 2001 | 5.08 | 6.06 | 3.63 |
| 2000 | 7.99 | 10.61 | 6.13 |
| 1999 | 6 | 7.84 | 4.81 |
| 1998 | 7.83 | 11.19 | 3.33 |
| 1997 | 7.6 | 10.61 | 5.45 |