| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.89 | 1.29 | 0.76 |
| 2024 | 0.75 | 1.31 | 0.55 |
| 2023 | 0.92 | 1.06 | 0.84 |
| 2022 | 0.9 | 1.16 | 0.78 |
| 2021 | 0.94 | 1.09 | 0.86 |
| 2020 | 1.11 | 1.4 | 0.9 |
| 2019 | 1.47 | 2 | 1.19 |
| 2018 | 2.01 | 3.14 | 1.48 |
| 2017 | 3.44 | 5.29 | 2.66 |
| 2016 | 5.08 | 11.85 | 3.32 |
| 2015 | 3.59 | 5.19 | 2.86 |
| 2014 | 2.6 | 3.31 | 2.27 |
| 2013 | 2.86 | 3.44 | 2.44 |
| 2012 | 3.95 | 5.64 | 2.56 |
| 2011 | 8.21 | 11.65 | 4.75 |
| 2010 | 12.31 | 15.37 | 9.79 |
| 2009 | 9.3 | 11.96 | 5.9 |
| 2008 | 13.08 | 22.45 | 5.14 |
| 2007 | 17.57 | 26.03 | 11.46 |
| 2006 | 7.59 | 17.16 | 2.02 |
| 2005 | 1.8 | 2.25 | 1.39 |
| 2004 | 2.57 | 3.42 | 1.81 |
| 2003 | 3.23 | 4.66 | 2.42 |
| 2002 | 4.52 | 5.02 | 3.34 |
| 2001 | 6.04 | 7.35 | 4.47 |
| 2000 | 6.45 | 8.14 | 4.03 |
| 1999 | 3.76 | 4.59 | 2.94 |
| 1998 | 3.59 | 4.26 | 2.9 |
| 1997 | 6.92 | 11.53 | 4.21 |