| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.19 | 1.31 | 1.11 |
| 2024 | 1.2 | 1.87 | 1.01 |
| 2023 | 1.34 | 1.74 | 1.05 |
| 2022 | 1.22 | 1.83 | 0.99 |
| 2021 | 1.22 | 1.44 | 1.03 |
| 2020 | 1.71 | 2.2 | 1.37 |
| 2019 | 2.22 | 3.29 | 1.78 |
| 2018 | 3.68 | 6.83 | 2.3 |
| 2017 | 3.85 | 5.14 | 2.92 |
| 2016 | 3.56 | 4.8 | 2.39 |
| 2015 | 3.27 | 5.6 | 1.89 |
| 2014 | 1.72 | 2.24 | 1.43 |
| 2013 | 1.62 | 2.22 | 1.19 |
| 2012 | 1.34 | 1.74 | 1.1 |
| 2011 | 2.06 | 2.83 | 1.18 |
| 2010 | 3.12 | 4.69 | 2.53 |
| 2009 | 4.56 | 6.48 | 2.1 |
| 2008 | 3.62 | 7.54 | 1.7 |
| 2007 | 7.42 | 13.31 | 2.77 |
| 2006 | 2.13 | 3.39 | 1.47 |
| 2005 | 1.71 | 2.42 | 1.38 |
| 2004 | 2.51 | 3.94 | 1.95 |
| 2003 | 3.55 | 4.36 | 2.84 |
| 2002 | 6.12 | 7.7 | 4.99 |
| 2001 | 6.94 | 7.81 | 5.85 |
| 2000 | 4.08 | 5.36 | 2.77 |
| 1999 | 3.14 | 3.79 | 2.61 |
| 1998 | 4.61 | 5.71 | 3.4 |
| 1997 | 5.46 | 8.97 | 3.86 |