| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2018 | 9.39 | 11.46 | 8.11 |
| 2017 | 9.30 | 10.54 | 7.68 |
| 2016 | 13.88 | 17.61 | 12.46 |
| 2015 | 12.65 | 16.83 | 9.51 |
| 2014 | 7.86 | 12.05 | 6.54 |
| 2013 | 8.26 | 9.51 | 6.59 |
| 2012 | 8.80 | 10.03 | 7.55 |
| 2011 | 10.24 | 11.63 | 9.09 |
| 2010 | 11.33 | 13.34 | 9.97 |
| 2009 | 19.68 | 25.32 | 16.22 |
| 2008 | 28.51 | 54.49 | 15.35 |
| 2007 | 35.91 | 57.52 | 17.59 |