| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.76 | 2.33 | 1.48 |
| 2024 | 1.39 | 2.3 | 0.89 |
| 2023 | 1.36 | 1.54 | 1.18 |
| 2022 | 1.43 | 2 | 1.05 |
| 2021 | 1.01 | 1.38 | 0.85 |
| 2020 | 1.09 | 1.34 | 0.95 |
| 2019 | 1.21 | 1.42 | 0.94 |
| 2018 | 1.16 | 1.49 | 0.95 |
| 2017 | 1.7 | 2.07 | 1.39 |
| 2016 | 2 | 2.42 | 1.52 |
| 2015 | 2.1 | 3.27 | 1.3 |
| 2014 | 1.51 | 1.78 | 1.36 |
| 2013 | 1.85 | 2.47 | 1.55 |
| 2012 | 2.25 | 3.13 | 1.53 |
| 2011 | 3.79 | 5.35 | 1.91 |
| 2010 | 2.53 | 3.93 | 1.77 |
| 2009 | 2.11 | 2.82 | 1.4 |
| 2008 | 2.1 | 3.82 | 1.09 |
| 2007 | 2.7 | 4.13 | 1.5 |
| 2006 | 1.27 | 1.74 | 0.73 |
| 2005 | 1.01 | 1.31 | 0.64 |
| 2004 | 1.63 | 2.32 | 1.15 |
| 2003 | 2.02 | 2.24 | 1.62 |
| 2002 | 2.47 | 4.19 | 1.69 |
| 2001 | 4.26 | 4.67 | 3.56 |
| 2000 | 4.21 | 5.17 | 3.5 |
| 1999 | 5.2 | 9.22 | 3.84 |
| 1998 | 8.09 | 10.54 | 6.34 |