| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.89 | 1.11 | 0.77 |
| 2024 | 0.78 | 0.93 | 0.63 |
| 2023 | 1 | 1.12 | 0.87 |
| 2022 | 1.04 | 1.33 | 0.85 |
| 2021 | 0.9 | 1.3 | 0.65 |
| 2020 | 0.84 | 1.07 | 0.69 |
| 2019 | 1.14 | 1.98 | 0.8 |
| 2018 | 1.18 | 1.85 | 0.76 |
| 2017 | 2.38 | 3.6 | 1.67 |
| 2016 | 14.47 | 46.13 | 2.52 |
| 2015 | 12.18 | 54.45 | 4.65 |
| 2014 | 4.93 | 6.55 | 4.1 |
| 2013 | 4.75 | 5.54 | 3.94 |
| 2012 | 5.38 | 6.73 | 4.22 |
| 2011 | 7.81 | 9.97 | 5.05 |
| 2010 | 7.19 | 9.05 | 5.12 |
| 2009 | 5.72 | 8.6 | 3.42 |
| 2008 | 6.15 | 10.92 | 2.41 |
| 2007 | 8.79 | 13.12 | 6.05 |
| 2006 | 5.43 | 6.71 | 4.2 |
| 2005 | 5.14 | 6.5 | 4.06 |
| 2004 | 5.32 | 8.95 | 2.54 |
| 2003 | 7.43 | 11.73 | 2.39 |
| 2002 | 4.85 | 6.43 | 2.6 |
| 2001 | 5.01 | 6.07 | 3.67 |
| 2000 | 4.43 | 5.51 | 3.09 |
| 1999 | 3.25 | 4.28 | 2.49 |
| 1998 | 4.13 | 5.72 | 2.97 |
| 1997 | 4.33 | 7.24 | 2.63 |