| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2018 | 9.29 | 12.67 | 7.69 |
| 2017 | 8.84 | 10.78 | 7.15 |
| 2016 | 13.06 | 15.93 | 11.38 |
| 2015 | 22.83 | 32.39 | 16.99 |
| 2014 | 8.08 | 10.96 | 6.94 |
| 2013 | 8.29 | 11.04 | 6.78 |
| 2012 | 10.11 | 11.73 | 8.78 |
| 2011 | 12.02 | 14.02 | 10.17 |
| 2010 | 14.00 | 18.82 | 11.1 |
| 2009 | 19.04 | 27.06 | 11.98 |
| 2008 | 27.52 | 53.11 | 12.59 |
| 2007 | 71.71 | 92.7 | 61.39 |