| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 2.8 | 3.45 | 2.42 |
| 2024 | 2.01 | 3.68 | 1.52 |
| 2023 | 1.9 | 2.56 | 1.5 |
| 2022 | 1.62 | 2.07 | 1.34 |
| 2021 | 1.82 | 2.65 | 1.49 |
| 2020 | 2.24 | 2.83 | 1.72 |
| 2019 | 2.18 | 3.09 | 1.71 |
| 2018 | 1.95 | 2.81 | 1.33 |
| 2017 | 3 | 3.71 | 2.2 |
| 2016 | 3.49 | 4.43 | 2.97 |
| 2015 | 5.47 | 9.9 | 3.32 |
| 2014 | 4.02 | 5.72 | 3.13 |
| 2013 | 2.66 | 4.69 | 1.9 |
| 2012 | 2.47 | 3.25 | 1.75 |
| 2011 | 3.33 | 4.16 | 2.44 |
| 2010 | 4.84 | 6.69 | 3.66 |
| 2009 | 4.95 | 5.98 | 4.11 |
| 2008 | 8.22 | 19.9 | 3.07 |
| 2007 | 10.46 | 17.5 | 3.66 |
| 2006 | 2.78 | 4 | 1.11 |
| 2005 | 1.19 | 1.6 | 0.83 |
| 2004 | 4.01 | 5.91 | 1.76 |
| 2003 | 5.95 | 8.21 | 4.21 |
| 2002 | 8.82 | 10.67 | 6.99 |
| 2001 | 12.42 | 14.49 | 8.52 |
| 2000 | 10.03 | 15.43 | 7.27 |
| 1999 | 5.67 | 8.39 | 4.36 |
| 1998 | 5.96 | 9.74 | 3.4 |
| 1997 | 2.98 | 4.1 | 2.27 |