| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.74 | 2.21 | 1.47 |
| 2024 | 1.34 | 2.48 | 0.95 |
| 2023 | 1.68 | 1.89 | 1.43 |
| 2022 | 2.03 | 2.66 | 1.66 |
| 2021 | 2.33 | 2.84 | 1.85 |
| 2020 | 2.47 | 2.96 | 2.03 |
| 2019 | 2.5 | 4.37 | 1.36 |
| 2018 | 1.67 | 2.26 | 1.28 |
| 2017 | 2.74 | 3.85 | 2.15 |
| 2016 | 2.86 | 3.54 | 2.25 |
| 2015 | 3.68 | 7.57 | 2.3 |
| 2014 | 2.35 | 3.8 | 1.56 |
| 2013 | 1.82 | 2.34 | 1.5 |
| 2012 | 2 | 2.7 | 1.59 |
| 2011 | 3.36 | 4.64 | 1.86 |
| 2010 | 3.41 | 4.29 | 2.51 |
| 2009 | 2.55 | 4.36 | 1.1 |
| 2008 | 2.07 | 3.84 | 0.86 |
| 2007 | 2.74 | 4.77 | 1.14 |
| 2006 | 1.02 | 1.32 | 0.75 |
| 2005 | 0.99 | 1.3 | 0.78 |
| 2004 | 1.6 | 2.14 | 1.26 |
| 2003 | 2.15 | 3.66 | 1.58 |
| 2002 | 2.87 | 3.16 | 2.31 |
| 2001 | 3.55 | 4.31 | 2.53 |
| 2000 | 4.73 | 5.47 | 3.38 |
| 1999 | 3.91 | 4.82 | 2.82 |