| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2018 | 14.77 | 18.94 | 10.03 |
| 2017 | 13.35 | 15.21 | 11.89 |
| 2016 | 15.94 | 18.82 | 13.51 |
| 2015 | 22.44 | 30.37 | 15.35 |
| 2014 | 15.46 | 22 | 1.85 |
| 2013 | 19.77 | 32.3 | 13.6 |
| 2012 | 23.44 | 27.71 | 20.78 |
| 2011 | 33.74 | 45.2 | 22.97 |
| 2010 | 40.98 | 51.04 | 32.65 |
| 2009 | 36.43 | 49.96 | 20.82 |
| 2008 | 26.93 | 41.35 | 14.77 |
| 2007 | 18.61 | 25.95 | 8.34 |