| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2018 | 31.11 | 38.46 | 21.13 |
| 2017 | 25.79 | 38.39 | 18.45 |
| 2016 | 17.41 | 20.89 | 14.28 |
| 2015 | 24.15 | 35.96 | 18.49 |
| 2014 | 21.36 | 25.14 | 18.14 |
| 2013 | 14.60 | 21.93 | 11.24 |
| 2012 | 12.66 | 15.03 | 9.84 |
| 2011 | 17.80 | 22.27 | 13.74 |
| 2010 | 30.52 | 37.02 | 23.68 |
| 2009 | 7.64 | 10.5 | 5.22 |
| 2008 | 22.25 | 32.02 | 12.25 |
| 2007 | 21.06 | 33.25 | 9.43 |