| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.52 | 1.94 | 1.26 |
| 2024 | 1.27 | 1.83 | 0.88 |
| 2023 | 1.19 | 1.33 | 1.05 |
| 2022 | 1.38 | 1.75 | 1.1 |
| 2021 | 1.95 | 2.91 | 1.5 |
| 2020 | 1.54 | 2.67 | 0.95 |
| 2019 | 1.29 | 1.81 | 1 |
| 2018 | 1.47 | 2.32 | 0.96 |
| 2017 | 2.55 | 3.18 | 1.95 |
| 2016 | 1.85 | 3.05 | 1.2 |
| 2015 | 2.33 | 3.48 | 1.27 |
| 2014 | 1.96 | 2.97 | 1.44 |
| 2013 | 1.91 | 2.74 | 1.36 |
| 2012 | 2.27 | 2.85 | 1.66 |
| 2011 | 3.86 | 5.55 | 2.03 |
| 2010 | 5.22 | 7.82 | 3.51 |
| 2009 | 4.4 | 7.32 | 1.96 |
| 2008 | 6.4 | 15.95 | 1.52 |
| 2007 | 11.37 | 23.59 | 3.99 |
| 2006 | 3.41 | 4.89 | 1.49 |
| 2005 | 1.33 | 1.77 | 0.91 |
| 2004 | 2.96 | 4.82 | 1.68 |
| 2003 | 3.14 | 4.48 | 2.71 |
| 2002 | 3.78 | 4.4 | 2.9 |
| 2001 | 4.78 | 5.89 | 3.1 |
| 2000 | 5.04 | 6.14 | 3.4 |
| 1999 | 3.31 | 4.16 | 2.37 |
| 1998 | 3.73 | 4.63 | 2.95 |
| 1997 | 4.94 | 7.65 | 3.43 |