| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2020 | 7.92 | 8.5 | 7.18 |
| 2019 | 8 | 8.67 | 7.47 |
| 2018 | 10.6 | 11.95 | 9.54 |
| 2017 | 11.71 | 15.68 | 7.89 |
| 2016 | 7.34 | 8.77 | 5.52 |
| 2015 | 11.9 | 24.45 | 6.36 |
| 2014 | 9.09 | 13.33 | 7.42 |
| 2013 | 10.05 | 12.81 | 7.86 |
| 2012 | 10.14 | 14.06 | 6.53 |
| 2011 | 8.66 | 11.88 | 6.8 |
| 2010 | 14.24 | 29.66 | 8.78 |
| 2009 | 17.39 | 30.19 | 5.56 |
| 2008 | 13.88 | 31.62 | 5.07 |
| 2007 | 36.34 | 54.15 | 22.04 |
| 2006 | 14.81 | 21.72 | 8.13 |
| 2005 | 10.43 | 20.25 | 6.45 |
| 2004 | 17.63 | 21.8 | 10.63 |
| 2003 | 14.8 | 16.22 | 12.95 |
| 2002 | 17.13 | 18.95 | 15.24 |
| 2001 | 22.02 | 29.69 | 14.45 |
| 2000 | 29.9 | 42.35 | 23.81 |
| 1999 | 28.25 | 34.19 | 21.09 |