| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.17 | 1.29 | 1.05 |
| 2024 | 1.1 | 1.39 | 0.91 |
| 2023 | 1.35 | 1.62 | 1.18 |
| 2022 | 1.44 | 1.69 | 1.09 |
| 2021 | 1.81 | 2.57 | 1.34 |
| 2020 | 1.42 | 1.96 | 1.1 |
| 2019 | 1.27 | 1.81 | 0.85 |
| 2018 | 1 | 1.55 | 0.73 |
| 2017 | 1.83 | 2.28 | 1.51 |
| 2016 | 1.59 | 2.08 | 1.16 |
| 2015 | 2.58 | 3.72 | 1.32 |
| 2014 | 1.46 | 1.86 | 1.24 |
| 2013 | 1.94 | 2.95 | 1.44 |
| 2012 | 2.78 | 4.02 | 1.81 |
| 2011 | 5.04 | 7.31 | 3.42 |
| 2010 | 6.16 | 7.92 | 4.28 |
| 2009 | 6.38 | 11.85 | 2.72 |
| 2008 | 8.74 | 17.16 | 1.88 |
| 2007 | 11.41 | 21.59 | 4.71 |
| 2006 | 4.78 | 8.24 | 2.52 |
| 2005 | 1.71 | 2.78 | 1.05 |
| 2004 | 1.84 | 2.48 | 1.29 |
| 2003 | 2.3 | 3.03 | 1.72 |
| 2002 | 4.28 | 4.86 | 3.7 |
| 2001 | 5.39 | 6.65 | 3.78 |
| 2000 | 7.23 | 11.31 | 5.54 |
| 1999 | 6.91 | 8.81 | 5.82 |
| 1998 | 9.61 | 12.14 | 7.33 |
| 1997 | 9.95 | 12.71 | 6.39 |