| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.82 | 2.07 | 1.68 |
| 2024 | 1.68 | 2.17 | 1.11 |
| 2023 | 1.19 | 1.33 | 1.08 |
| 2022 | 1.25 | 1.54 | 1.1 |
| 2021 | 1.43 | 1.71 | 1.28 |
| 2020 | 1.69 | 2.93 | 1.17 |
| 2019 | 1.67 | 2.14 | 1.45 |
| 2018 | 1.99 | 2.65 | 1.46 |
| 2017 | 2.86 | 3.99 | 2.32 |
| 2016 | 2.42 | 2.8 | 2.11 |
| 2015 | 3.66 | 5.29 | 2.25 |
| 2014 | 2.52 | 4.7 | 1.94 |
| 2013 | 1.84 | 2.85 | 1.29 |
| 2012 | 1.71 | 1.9 | 1.57 |
| 2011 | 1.97 | 2.49 | 1.5 |
| 2010 | 2.23 | 2.91 | 1.79 |
| 2009 | 2.38 | 3.03 | 1.6 |
| 2008 | 3.25 | 7.12 | 1.4 |
| 2007 | 6.35 | 8.49 | 3.7 |
| 2006 | 3.31 | 4.4 | 2.53 |
| 2005 | 4.19 | 5.67 | 3.04 |
| 2004 | 5.5 | 8.03 | 3.52 |
| 2003 | 6.01 | 6.94 | 5.28 |
| 2002 | 6.4 | 7.4 | 5.77 |
| 2001 | 6.88 | 7.87 | 5.8 |
| 2000 | 5.19 | 6.35 | 3.47 |
| 1999 | 3.54 | 4.96 | 2.75 |
| 1998 | 3.41 | 4.54 | 2.54 |