| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.59 | 0.67 | 0.53 |
| 2024 | 0.7 | 0.79 | 0.57 |
| 2023 | 0.67 | 0.83 | 0.61 |
| 2022 | 0.7 | 0.81 | 0.62 |
| 2021 | 0.72 | 0.8 | 0.65 |
| 2020 | 0.84 | 0.91 | 0.77 |
| 2019 | 0.98 | 1.23 | 0.84 |
| 2018 | 1.09 | 1.46 | 0.85 |
| 2017 | 1.78 | 2.21 | 1.38 |
| 2016 | 1.73 | 2.04 | 1.45 |
| 2015 | 2.46 | 4.3 | 1.6 |
| 2014 | 1.17 | 2.03 | 0.88 |
| 2013 | 1.02 | 1.19 | 0.84 |
| 2012 | 1.34 | 2.4 | 0.9 |
| 2011 | 1.69 | 2.2 | 1.24 |
| 2010 | 2.09 | 2.89 | 1.49 |
| 2009 | 2.53 | 3.16 | 2.16 |
| 2008 | 2.96 | 4.89 | 1.68 |
| 2007 | 3.57 | 5.18 | 1.46 |
| 2006 | 1.17 | 1.53 | 0.94 |
| 2005 | 1.14 | 1.36 | 0.89 |
| 2004 | 1.79 | 2.45 | 1.34 |
| 2003 | 2.37 | 2.8 | 1.82 |
| 2002 | 3.87 | 5.07 | 2.96 |
| 2001 | 4.33 | 5.22 | 3.51 |
| 2000 | 3.45 | 3.97 | 2.99 |
| 1999 | 4.64 | 8.64 | 2.72 |
| 1998 | 5.89 | 7.23 | 3.29 |
| 1997 | 4.27 | 6.97 | 3.13 |