| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2021 | 19.18 | 24.12 | 12.23 |
| 2020 | 16.99 | 25.7 | 10.89 |
| 2019 | 11.77 | 14.5 | 7.68 |
| 2018 | 11.68 | 17.57 | 7.65 |
| 2017 | 13.14 | 15.35 | 10.36 |
| 2016 | 9.03 | 13.33 | 7.71 |
| 2015 | 9.44 | 13.33 | 6.69 |
| 2014 | 7.87 | 10.02 | 6.34 |
| 2013 | 10.68 | 13.15 | 9 |
| 2012 | 11.27 | 12.67 | 9.55 |
| 2011 | 12.77 | 16.77 | 8.95 |
| 2010 | 14.79 | 20.36 | 11.38 |
| 2009 | 17.27 | 21.77 | 11.41 |
| 2008 | 24.93 | 57.03 | 9.47 |
| 2007 | 35.64 | 50.99 | 16.45 |
| 2006 | 12.83 | 16.48 | 10.53 |
| 2005 | 12.08 | 15.07 | 10.1 |
| 2004 | 16.35 | 18.45 | 13.4 |
| 2003 | 14.28 | 16.32 | 12.99 |
| 2002 | 17.22 | 20.29 | 15.08 |
| 2001 | 20.96 | 26.88 | 15.25 |
| 2000 | 26.55 | 31.41 | 20.93 |
| 1999 | 25.07 | 36.99 | 17.6 |
| 1998 | 26.92 | 36.15 | 14.29 |
| 1997 | 29.48 | 40.23 | 23.66 |