| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2024 | 8.3 | 10.83 | 6.79 |
| 2023 | 10.91 | 13.1 | 8.67 |
| 2022 | 8.55 | 11.39 | 6.82 |
| 2021 | 11.28 | 15.42 | 8.52 |
| 2020 | 10.2 | 13.67 | 5.51 |
| 2019 | 4.85 | 6.65 | 2.91 |
| 2018 | 3.86 | 5.34 | 2.52 |
| 2017 | 3.22 | 3.95 | 2.76 |
| 2016 | 4.52 | 7.63 | 3.33 |
| 2015 | 8.41 | 12.7 | 5.01 |
| 2014 | 5.28 | 7.37 | 4.03 |
| 2013 | 4.48 | 8.1 | 3 |
| 2012 | 4 | 4.92 | 3.15 |
| 2011 | 5.3 | 6.98 | 4.01 |
| 2010 | 7.86 | 10.46 | 6.49 |
| 2009 | 7.29 | 9.19 | 5.25 |
| 2008 | 8.18 | 16.13 | 3.68 |
| 2007 | 12.3 | 19.05 | 6.13 |
| 2006 | 7.01 | 10.26 | 5.45 |
| 2005 | 4.97 | 7.73 | 3.45 |
| 2004 | 6.08 | 8.76 | 4.84 |
| 2003 | 7.69 | 9.38 | 5.5 |
| 2002 | 10.56 | 17.06 | 8.28 |
| 2001 | 16.46 | 19.65 | 11.47 |
| 2000 | 7.59 | 14.18 | 5.15 |
| 1999 | 3.28 | 4.77 | 2.05 |
| 1998 | 2.14 | 2.73 | 1.7 |
| 1997 | 1.91 | 2.58 | 1.39 |