| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2024 | 0.76 | 0.99 | 0.61 |
| 2023 | 0.94 | 1.17 | 0.79 |
| 2022 | 1.2 | 1.78 | 0.88 |
| 2021 | 1.37 | 1.9 | 1.08 |
| 2020 | 1.25 | 1.51 | 1.07 |
| 2019 | 1.23 | 1.61 | 1.06 |
| 2018 | 1.31 | 1.84 | 0.99 |
| 2017 | 1.66 | 1.83 | 1.46 |
| 2016 | 1.65 | 1.98 | 1.33 |
| 2015 | 3.32 | 5.87 | 1.26 |
| 2014 | 2.02 | 4.53 | 1.59 |
| 2013 | 2.31 | 3.09 | 1.88 |
| 2012 | 2.51 | 3.01 | 1.89 |
| 2011 | 4.57 | 7.63 | 1.93 |
| 2010 | 107.77 | 570.25 | 4.39 |
| 2009 | 7.19 | 7.28 | 7.06 |
| 2008 | 7.47 | 7.58 | 7.26 |
| 2007 | 7.82 | 8.35 | 7.52 |
| 2006 | 5.45 | 8.82 | 2.1 |
| 2005 | 2.56 | 3.76 | 1.83 |
| 2004 | 4.23 | 5.93 | 3.05 |
| 2003 | 5.89 | 7.23 | 4.26 |
| 2002 | 4.05 | 4.71 | 2.64 |
| 2001 | 4.59 | 5.42 | 3.19 |
| 2000 | 4.85 | 5.41 | 3.51 |
| 1999 | 6.14 | 10 | 4.16 |
| 1998 | 5.62 | 8.45 | 3.81 |