| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2020 | 24.05 | 26.69 | 21.2 |
| 2019 | 29.75 | 42.85 | 21.06 |
| 2018 | 22.35 | 24.92 | 18.9 |
| 2017 | 31.24 | 40.26 | 23.21 |
| 2016 | 34.98 | 40.54 | 29.31 |
| 2015 | 37.12 | 61.85 | 25.77 |
| 2014 | 22.91 | 28.79 | 18.96 |
| 2013 | 18.5 | 22.82 | 15.73 |
| 2012 | 18 | 21.29 | 14.6 |
| 2011 | 23.1 | 31.46 | 15.36 |
| 2010 | 22.37 | 28.01 | 17.4 |
| 2009 | 27.09 | 33.12 | 20.49 |
| 2008 | 39.46 | 76.76 | 18.07 |
| 2007 | 57.6 | 117.43 | 18.59 |
| 2006 | 14.05 | 19.23 | 9.85 |
| 2005 | 12.8 | 19.48 | 9.25 |
| 2004 | 21.22 | 29.34 | 15.78 |
| 2003 | 31.61 | 38.51 | 22.49 |
| 2002 | 42.23 | 51.53 | 31.03 |