| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.7 | 0.85 | 0.61 |
| 2024 | 0.61 | 1.03 | 0.43 |
| 2023 | 0.78 | 1.01 | 0.62 |
| 2022 | 0.72 | 0.94 | 0.59 |
| 2021 | 0.72 | 0.87 | 0.58 |
| 2020 | 0.92 | 1.18 | 0.74 |
| 2019 | 0.88 | 1.23 | 0.69 |
| 2018 | 1.06 | 1.51 | 0.73 |
| 2017 | 1.67 | 2.05 | 1.38 |
| 2016 | 2.08 | 3.11 | 1.63 |
| 2015 | 2.59 | 4 | 1.66 |
| 2014 | 2.24 | 2.68 | 1.82 |
| 2013 | 2.27 | 2.82 | 1.92 |
| 2012 | 2.14 | 2.57 | 1.76 |
| 2011 | 3.25 | 4.5 | 1.97 |
| 2010 | 18.75 | 82.32 | 3.35 |
| 2009 | 16.85 | 80.85 | 4.02 |
| 2008 | 5.72 | 10.68 | 2.85 |
| 2007 | 7.06 | 10.84 | 2.47 |
| 2006 | 2.53 | 3.01 | 1.99 |
| 2005 | 2.88 | 4.99 | 1.69 |
| 2004 | 4.09 | 4.72 | 3.25 |
| 2003 | 4.7 | 6.29 | 3.34 |
| 2002 | 10.48 | 15.64 | 6.87 |
| 2001 | 15.92 | 20.24 | 11.68 |
| 2000 | 12.26 | 18.51 | 6.86 |
| 1999 | 4.75 | 6.67 | 2.96 |
| 1998 | 4.09 | 5.77 | 2.96 |
| 1997 | 3.85 | 5.29 | 2.21 |