| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2018 | 25.23 | 37.01 | 12.97 |
| 2017 | 25.72 | 36.14 | 16.04 |
| 2016 | 22.18 | 25.53 | 18 |
| 2015 | 29.99 | 40.3 | 20.25 |
| 2014 | 28.30 | 43.17 | 21.78 |
| 2013 | 37.93 | 47.68 | 20.7 |
| 2012 | 26.08 | 36.95 | 15.88 |
| 2011 | 31.26 | 38.81 | 24.07 |
| 2010 | 30.31 | 51.02 | 17.27 |
| 2009 | 26.51 | 41.73 | 21.66 |
| 2008 | 22.99 | 32.88 | 11.64 |