| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2020 | 8.87 | 10.64 | 7.72 |
| 2019 | 10.82 | 20.02 | 7.66 |
| 2018 | 12.31 | 17.39 | 7.36 |
| 2017 | 16.17 | 19.97 | 13.06 |
| 2016 | 15.84 | 19.82 | 8.49 |
| 2015 | 15.11 | 22.95 | 10.55 |
| 2014 | 13 | 20.36 | 8.85 |
| 2013 | 17.51 | 26.62 | 12.88 |
| 2012 | 13.05 | 16.21 | 9.33 |
| 2011 | 16.56 | 23.87 | 9.15 |
| 2010 | 23.78 | 32.94 | 17.47 |
| 2009 | 21.09 | 30.11 | 7.92 |
| 2008 | 19.43 | 38.39 | 5.74 |
| 2007 | 29.16 | 43.01 | 13.99 |
| 2006 | 13.39 | 16.38 | 11.09 |
| 2005 | 17.01 | 24.58 | 10.75 |
| 2004 | 24.15 | 32.66 | 12.23 |