| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.72 | 0.77 | 0.65 |
| 2024 | 0.69 | 0.83 | 0.57 |
| 2023 | 0.9 | 0.99 | 0.77 |
| 2022 | 0.91 | 1.13 | 0.73 |
| 2021 | 0.89 | 1.02 | 0.83 |
| 2020 | 0.99 | 1.09 | 0.87 |
| 2019 | 1.26 | 2.28 | 0.92 |
| 2018 | 2.3 | 4.13 | 1.36 |
| 2017 | 4.31 | 6.64 | 2.85 |
| 2016 | 8.06 | 10.87 | 5.44 |
| 2015 | 6.7 | 11.19 | 3.54 |
| 2014 | 5.14 | 7.39 | 3.54 |
| 2013 | 3.56 | 4.15 | 2.94 |
| 2012 | 3.07 | 3.88 | 2.53 |
| 2011 | 4.38 | 5.84 | 2.73 |
| 2010 | 6.82 | 9.72 | 4.85 |
| 2009 | 6.16 | 7.84 | 3.21 |
| 2008 | 5.08 | 8.31 | 2.73 |
| 2007 | 6.04 | 8.7 | 4.14 |
| 2006 | 4.03 | 5.17 | 2.79 |
| 2005 | 2.08 | 4.1 | 1.27 |
| 2004 | 2.11 | 4.41 | 1.29 |
| 2003 | 1.58 | 1.88 | 1.25 |
| 2002 | 1.81 | 2.03 | 1.5 |
| 2001 | 2.62 | 3.8 | 1.68 |
| 2000 | 3.13 | 3.71 | 2.53 |
| 1999 | 3.3 | 4.7 | 2.67 |
| 1998 | 4.61 | 5.7 | 3.57 |
| 1997 | 5.84 | 11.08 | 3.4 |