| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.6 | 1.8 | 1.45 |
| 2024 | 1.69 | 1.97 | 1.38 |
| 2023 | 2.95 | 4.27 | 1.78 |
| 2022 | 3.6 | 4.18 | 2.93 |
| 2021 | 3.64 | 5.15 | 2.55 |
| 2020 | 2.62 | 4.19 | 1.72 |
| 2019 | 1.84 | 2.32 | 1.51 |
| 2018 | 2.31 | 3.06 | 1.6 |
| 2017 | 2.18 | 2.5 | 1.82 |
| 2016 | 3.49 | 4.86 | 2.21 |
| 2015 | 3.72 | 5.59 | 2.52 |
| 2014 | 2.64 | 4.48 | 1.94 |
| 2013 | 2 | 2.56 | 1.65 |
| 2012 | 2.32 | 2.69 | 1.85 |
| 2011 | 2.7 | 3.35 | 2.25 |
| 2010 | 3.89 | 5.23 | 2.8 |
| 2009 | 3.27 | 4.2 | 1.68 |
| 2008 | 2.82 | 6.31 | 1.25 |
| 2007 | 5.17 | 6.96 | 3.43 |
| 2006 | 2.78 | 3.69 | 1.93 |
| 2005 | 1.94 | 2.55 | 1.51 |
| 2004 | 1.81 | 2.36 | 1.49 |
| 2003 | 2.19 | 2.91 | 1.51 |
| 2002 | 3.06 | 4.02 | 2.66 |
| 2001 | 4.51 | 5.55 | 3.51 |
| 2000 | 4.19 | 5.01 | 2.95 |
| 1999 | 3.21 | 3.9 | 2.68 |
| 1998 | 3.07 | 3.71 | 2.38 |
| 1997 | 3.2 | 4.31 | 2.46 |