| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.71 | 2.75 | 1.57 |
| 2024 | 1.64 | 2.05 | 1.37 |
| 2023 | 1.95 | 2.24 | 1.68 |
| 2022 | 1.86 | 2.41 | 1.51 |
| 2021 | 1.84 | 2.13 | 1.64 |
| 2020 | 2.04 | 2.48 | 1.86 |
| 2019 | 2.62 | 4.18 | 1.8 |
| 2018 | 2.33 | 3.01 | 1.59 |
| 2017 | 2.88 | 3.89 | 2.34 |
| 2016 | 3.53 | 4.39 | 2.86 |
| 2015 | 5.47 | 9.75 | 3.37 |
| 2014 | 4.38 | 6.58 | 3.31 |
| 2013 | 4.32 | 6.71 | 3.47 |
| 2012 | 4.57 | 5.75 | 3.5 |
| 2011 | 6.64 | 8.63 | 4.59 |
| 2010 | 7.09 | 8.41 | 6.14 |
| 2009 | 5.27 | 7.36 | 2.98 |
| 2008 | 4.58 | 7.19 | 2.26 |
| 2007 | 6.1 | 9.43 | 3.5 |
| 2006 | 3.21 | 4.52 | 2.2 |
| 2005 | 2.57 | 3.7 | 1.67 |
| 2004 | 4.75 | 8.13 | 3.45 |
| 2003 | 9.48 | 12 | 4.15 |
| 2002 | 5.64 | 7.93 | 4.42 |
| 2001 | 9.48 | 11.32 | 7.24 |
| 2000 | 12.13 | 18.19 | 8.19 |
| 1999 | 8.92 | 13.71 | 3.93 |
| 1998 | 4.57 | 5.95 | 3.24 |