| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.11 | 1.39 | 1.03 |
| 2024 | 1.07 | 1.32 | 0.89 |
| 2023 | 1.05 | 1.25 | 0.97 |
| 2022 | 1.15 | 1.72 | 0.99 |
| 2021 | 1.38 | 1.78 | 1.08 |
| 2020 | 1.71 | 2.18 | 1.31 |
| 2019 | 1.62 | 2.4 | 1.31 |
| 2018 | 1.62 | 2.08 | 1.3 |
| 2017 | 2.37 | 3.24 | 1.74 |
| 2016 | 2.67 | 3.47 | 2.4 |
| 2015 | 4.71 | 7.14 | 2.49 |
| 2014 | 8.32 | 23.72 | 2.22 |
| 2013 | 4.01 | 21.68 | 2.59 |
| 2012 | 3.07 | 4.23 | 2.71 |
| 2011 | 4.64 | 6.31 | 2.84 |
| 2010 | 6.69 | 8.79 | 4.9 |
| 2009 | 6.84 | 8.72 | 4.3 |
| 2008 | 6.24 | 11.45 | 3.15 |
| 2007 | 6.61 | 10.51 | 2.46 |
| 2006 | 2.17 | 2.63 | 1.63 |
| 2005 | 1.89 | 2.38 | 1.54 |
| 2004 | 2.23 | 3.24 | 1.57 |
| 2003 | 2.62 | 3.18 | 1.94 |
| 2002 | 3.64 | 4.1 | 2.55 |
| 2001 | 4.81 | 5.98 | 3.48 |
| 2000 | 4.44 | 5.38 | 3.08 |
| 1999 | 6.17 | 8.4 | 4.36 |
| 1998 | 6.62 | 9.29 | 4.6 |
| 1997 | 6.33 | 10.1 | 2.37 |