| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2020 | 9.95 | 12.75 | 7.1 |
| 2019 | 8.66 | 9.81 | 7.58 |
| 2018 | 10.34 | 12.99 | 7.58 |
| 2017 | 10.38 | 11.9 | 8.32 |
| 2016 | 7.78 | 8.97 | 6.81 |
| 2015 | 8.63 | 11.14 | 5.47 |
| 2014 | 6.95 | 9.31 | 6.01 |
| 2013 | 7.42 | 8.94 | 6.19 |
| 2012 | 7.64 | 10.36 | 5.58 |
| 2011 | 10.45 | 13.98 | 6.73 |
| 2010 | 24.86 | 73.47 | 10.92 |
| 2009 | 1027.09 | 3011.58 | 12.25 |
| 2008 | 17.26 | 41.27 | 8.46 |
| 2007 | 53.22 | 82.25 | 31.4 |
| 2006 | 15.44 | 49.15 | 9.89 |
| 2005 | 10.78 | 17.14 | 6.69 |
| 2004 | 15.79 | 26.81 | 8.28 |
| 2003 | 21.26 | 28.01 | 16.71 |
| 2002 | 23.43 | 26.18 | 19.33 |
| 2001 | 27.97 | 35.24 | 20.94 |
| 2000 | 22.37 | 27.3 | 19.27 |
| 1999 | 22.5 | 29.88 | 17.7 |
| 1998 | 27.37 | 31.53 | 23.48 |