| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 2.85 | 4 | 1.82 |
| 2024 | 1.89 | 2.66 | 1.25 |
| 2023 | 2.78 | 3.62 | 2.29 |
| 2022 | 3.91 | 5.46 | 2.47 |
| 2021 | 2.15 | 4.71 | 1.74 |
| 2020 | 2.42 | 3.36 | 2.12 |
| 2019 | 2.71 | 3.62 | 2.25 |
| 2018 | 2.73 | 3.49 | 2.11 |
| 2017 | 3.94 | 5.92 | 3.31 |
| 2016 | 6.74 | 9.85 | 5.66 |
| 2015 | 5.98 | 8.33 | 3.06 |
| 2014 | 3.66 | 4.06 | 2.91 |
| 2013 | 24.31 | 51.42 | 3.14 |
| 2012 | 24.2 | 30.1 | 20.4 |
| 2011 | 26.72 | 32.28 | 20.6 |
| 2010 | 25.3 | 33.47 | 17.44 |
| 2009 | 16.89 | 21.74 | 10.5 |
| 2008 | 19.65 | 48.14 | 7.61 |
| 2007 | 27.32 | 42.1 | 14.37 |
| 2006 | 9.87 | 16.36 | 5.05 |
| 2005 | 4.83 | 6.55 | 3.22 |
| 2004 | 7.14 | 10.01 | 4.84 |
| 2003 | 8.96 | 11.38 | 5.65 |
| 2002 | 11.78 | 14.54 | 8.58 |
| 2001 | 16.17 | 20.15 | 14.09 |
| 2000 | 14.44 | 19.65 | 8.29 |
| 1999 | 8.24 | 10.97 | 5.88 |
| 1998 | 5.72 | 7.57 | 3.82 |
| 1997 | 3.37 | 4.44 | 2.47 |