| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.51 | 2.01 | 1.27 |
| 2024 | 1.18 | 1.91 | 0.78 |
| 2023 | 1.59 | 2.09 | 1.25 |
| 2022 | 1.41 | 1.91 | 1.13 |
| 2021 | 1.13 | 1.49 | 0.77 |
| 2020 | 0.8 | 1.21 | 0.38 |
| 2019 | 0.56 | 0.72 | 0.46 |
| 2018 | 0.62 | 0.84 | 0.46 |
| 2017 | 1.05 | 1.3 | 0.79 |
| 2016 | 1.65 | 3.1 | 1.21 |
| 2015 | 2.89 | 4.75 | 1.87 |
| 2014 | 2.35 | 3.84 | 1.86 |
| 2013 | 2.64 | 3.6 | 2.17 |
| 2012 | 2.77 | 3.59 | 2.01 |
| 2011 | 3.7 | 4.98 | 2.78 |
| 2010 | 4.51 | 5.57 | 3.59 |
| 2009 | 2.98 | 4.64 | 1.53 |
| 2008 | 2.85 | 5.44 | 1.28 |
| 2007 | 3.94 | 5.71 | 2.84 |
| 2006 | 2.43 | 3.34 | 1.89 |
| 2005 | 2.3 | 2.97 | 1.87 |
| 2004 | 3.4 | 4.6 | 2.72 |
| 2003 | 4.16 | 5.46 | 2.75 |
| 2002 | 4.2 | 5.11 | 2.72 |
| 2001 | 5.81 | 6.89 | 4.08 |
| 2000 | 6.88 | 9.84 | 5.82 |
| 1999 | 5.71 | 8.67 | 3.7 |
| 1998 | 5.11 | 6.41 | 3.82 |