| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 2.67 | 2.87 | 2.43 |
| 2024 | 2.97 | 3.59 | 2.02 |
| 2023 | 2.75 | 3.21 | 2.3 |
| 2022 | 2.55 | 3.05 | 1.71 |
| 2021 | 2.03 | 3.52 | 1.64 |
| 2020 | 2.1 | 2.53 | 1.84 |
| 2019 | 2.15 | 3.42 | 1.53 |
| 2018 | 2.29 | 3.22 | 1.39 |
| 2017 | 3.06 | 3.3 | 2.54 |
| 2016 | 3.39 | 4.37 | 3.04 |
| 2015 | 4.44 | 7.67 | 2.97 |
| 2014 | 2.55 | 3.95 | 1.8 |
| 2013 | 2.08 | 2.4 | 1.68 |
| 2012 | 2.44 | 3.11 | 1.94 |
| 2011 | 3.67 | 4.78 | 2.22 |
| 2010 | 4.09 | 5.23 | 3.28 |
| 2009 | 3.22 | 4.27 | 2.01 |
| 2008 | 3.38 | 6.12 | 1.44 |
| 2007 | 4.55 | 7.56 | 2.09 |
| 2006 | 2.03 | 2.7 | 1.49 |
| 2005 | 1.82 | 2.56 | 1.26 |
| 2004 | 8.62 | 27.61 | 2.53 |
| 2003 | 16.53 | 18.9 | 14.49 |
| 2002 | 7.83 | 12.19 | 3.15 |
| 2001 | 8.53 | 12.96 | 2.83 |
| 2000 | 14.74 | 21.53 | 9.61 |
| 1999 | 14.83 | 39.85 | 7.29 |
| 1998 | 14.82 | 20.05 | 8.74 |