| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.73 | 0.81 | 0.66 |
| 2024 | 0.69 | 0.87 | 0.54 |
| 2023 | 0.57 | 0.66 | 0.48 |
| 2022 | 0.58 | 0.67 | 0.46 |
| 2021 | 0.63 | 0.85 | 0.44 |
| 2020 | 0.41 | 0.52 | 0.33 |
| 2019 | 0.56 | 0.84 | 0.42 |
| 2018 | 0.66 | 0.89 | 0.49 |
| 2017 | 1.01 | 1.26 | 0.74 |
| 2016 | 1.27 | 1.67 | 1.05 |
| 2015 | 2.03 | 2.77 | 1.32 |
| 2014 | 2.13 | 2.67 | 1.93 |
| 2013 | 1.78 | 2.37 | 1.55 |
| 2012 | 1.55 | 1.91 | 1.22 |
| 2011 | 2.09 | 3.06 | 1.26 |
| 2010 | 2.47 | 3.67 | 1.93 |
| 2009 | 1.54 | 2.43 | 0.81 |
| 2008 | 1.46 | 2.89 | 0.64 |
| 2007 | 2.85 | 3.41 | 2.33 |
| 2006 | 1.88 | 2.63 | 1.07 |
| 2005 | 0.52 | 1.06 | 0.33 |
| 2004 | 0.7 | 1.23 | 0.4 |
| 2003 | 1.01 | 1.16 | 0.83 |
| 2002 | 0.83 | 0.98 | 0.61 |
| 2001 | 0.84 | 1.32 | 0.4 |
| 2000 | 0.33 | 0.45 | 0.23 |
| 1999 | 0.35 | 0.52 | 0.25 |
| 1998 | 0.41 | 0.75 | 0.23 |
| 1997 | 0.42 | 0.57 | 0.31 |