| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2018 | 12.99 | 15.91 | 8.33 |
| 2017 | 13.22 | 16.13 | 11.57 |
| 2016 | 11.27 | 12.75 | 9.79 |
| 2015 | 12.60 | 15.36 | 9.88 |
| 2014 | 8.69 | 12.63 | 7.27 |
| 2013 | 11.82 | 14.03 | 9.42 |
| 2012 | 10.05 | 11.69 | 7.59 |
| 2011 | 9.92 | 12 | 8.15 |
| 2010 | 11.57 | 14.82 | 8.88 |
| 2009 | 13.15 | 19.01 | 8.55 |
| 2008 | 15.40 | 28.98 | 6.76 |
| 2007 | 26.34 | 39.93 | 14.35 |