| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2019 | 7.94 | 9.23 | 6.82 |
| 2018 | 8.08 | 10.39 | 5.26 |
| 2017 | 9.40 | 11.24 | 8.68 |
| 2016 | 9.45 | 12.23 | 8.29 |
| 2015 | 12.98 | 21.46 | 8.91 |
| 2014 | 6.96 | 10.16 | 6.03 |
| 2013 | 7.43 | 8.54 | 6.64 |
| 2012 | 8.04 | 9.97 | 6.12 |
| 2011 | 12.12 | 15.46 | 8.16 |
| 2010 | 16.31 | 21.84 | 12.85 |
| 2009 | 15.83 | 20.02 | 11.62 |
| 2008 | 18.66 | 34.98 | 11.9 |
| 2007 | 29.22 | 38.5 | 18.82 |
| 2006 | 17.41 | 21.73 | 13.72 |
| 2005 | 22.48 | 25.66 | 19.09 |
| 2004 | 30.10 | 38.19 | 22.17 |
| 2003 | 31.25 | 37.23 | 28.32 |