| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.51 | 1.63 | 1.35 |
| 2024 | 1.13 | 2.18 | 0.7 |
| 2023 | 1.52 | 1.85 | 1.16 |
| 2022 | 1.24 | 1.56 | 1.01 |
| 2021 | 1.24 | 1.42 | 1.12 |
| 2020 | 1.35 | 1.65 | 1.16 |
| 2019 | 1.48 | 2.01 | 1.26 |
| 2018 | 1.71 | 2.26 | 1.32 |
| 2017 | 2.24 | 3.09 | 1.53 |
| 2016 | 3.4 | 5.32 | 2.82 |
| 2015 | 3.74 | 5.35 | 2.17 |
| 2014 | 3.22 | 4.22 | 2.26 |
| 2013 | 2.68 | 3.53 | 2.24 |
| 2012 | 2.74 | 3.3 | 2.01 |
| 2011 | 2.66 | 3.64 | 2.12 |
| 2010 | 2.59 | 3.6 | 1.5 |
| 2009 | 2.56 | 4.17 | 1.03 |
| 2008 | 3.18 | 10.05 | 0.84 |
| 2007 | 7.89 | 12.36 | 4.93 |
| 2006 | 2.49 | 4.98 | 1.33 |
| 2005 | 1.96 | 2.79 | 1.47 |
| 2004 | 2.14 | 3.01 | 1.47 |
| 2003 | 2.11 | 2.94 | 1.41 |
| 2002 | 3.55 | 3.99 | 2.9 |
| 2001 | 4.86 | 6.14 | 3.43 |
| 2000 | 5.82 | 7.25 | 4.49 |
| 1999 | 4.02 | 5.24 | 2.99 |
| 1998 | 4.44 | 5.69 | 3.35 |
| 1997 | 5.39 | 7.94 | 3.76 |