| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.39 | 1.68 | 1.22 |
| 2024 | 1.29 | 1.65 | 0.88 |
| 2023 | 1.51 | 1.83 | 1.27 |
| 2022 | 2.39 | 3.81 | 1.26 |
| 2021 | 4.34 | 5.5 | 3.63 |
| 2020 | 4.24 | 6.33 | 2.27 |
| 2019 | 2.13 | 2.82 | 1.56 |
| 2018 | 2.68 | 4.71 | 1.81 |
| 2017 | 1.96 | 2.69 | 1.51 |
| 2016 | 1.9 | 2.45 | 1.68 |
| 2015 | 2.43 | 4.12 | 1.48 |
| 2014 | 1.98 | 2.74 | 1.58 |
| 2013 | 1.88 | 2.23 | 1.55 |
| 2012 | 2.13 | 2.7 | 1.59 |
| 2011 | 3.05 | 4.46 | 1.85 |
| 2010 | 3.85 | 5.13 | 3 |
| 2009 | 2.45 | 3.84 | 0.9 |
| 2008 | 2.17 | 4.56 | 0.8 |
| 2007 | 3.2 | 5.09 | 1.11 |
| 2006 | 1.11 | 1.37 | 0.86 |
| 2005 | 1 | 1.56 | 0.71 |
| 2004 | 1.89 | 2.52 | 1.45 |
| 2003 | 1.91 | 2.29 | 1.46 |
| 2002 | 2.83 | 3.62 | 2 |
| 2001 | 4.44 | 7.45 | 2.35 |
| 2000 | 11.56 | 22.06 | 4.82 |
| 1999 | 10.32 | 17.36 | 6.59 |
| 1998 | 9.82 | 13.18 | 4.59 |
| 1997 | 8.95 | 12.67 | 4.08 |