| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.36 | 1.98 | 0.92 |
| 2024 | 0.86 | 1.25 | 0.68 |
| 2023 | 0.84 | 0.95 | 0.77 |
| 2022 | 0.88 | 1.09 | 0.72 |
| 2021 | 0.91 | 1.05 | 0.79 |
| 2020 | 1.31 | 1.64 | 1.02 |
| 2019 | 1.43 | 1.8 | 1.14 |
| 2018 | 1.3 | 1.78 | 0.98 |
| 2017 | 2.32 | 2.91 | 1.72 |
| 2016 | 2.52 | 3.76 | 1.68 |
| 2015 | 2.99 | 5.47 | 1.55 |
| 2014 | 1.62 | 2.55 | 1.19 |
| 2013 | 1.59 | 1.94 | 1.22 |
| 2012 | 1.45 | 2.26 | 1.03 |
| 2011 | 1.63 | 1.97 | 1.27 |
| 2010 | 3.47 | 5.44 | 1.78 |
| 2009 | 2.93 | 4.44 | 1.6 |
| 2008 | 3.03 | 6.37 | 1.23 |
| 2007 | 4.27 | 7.19 | 1.62 |
| 2006 | 1.39 | 1.7 | 1.05 |
| 2005 | 1.45 | 2.06 | 1.06 |
| 2004 | 3.05 | 5.27 | 1.98 |
| 2003 | 7.04 | 8.99 | 3.41 |
| 2002 | 8.36 | 9.19 | 7.81 |
| 2001 | 9.48 | 10.74 | 8.15 |
| 2000 | 12.52 | 16.17 | 9.09 |
| 1999 | 8.23 | 11.15 | 4.55 |
| 1998 | 4.68 | 5.37 | 3.59 |