| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2019 | 6.88 | 8.12 | 5.85 |
| 2018 | 8.12 | 12.07 | 5.54 |
| 2017 | 11.83 | 14.1 | 9.39 |
| 2016 | 15.50 | 19.3 | 11.29 |
| 2015 | 18.11 | 29.59 | 9.57 |
| 2014 | 6.58 | 11.71 | 4.96 |
| 2013 | 7.21 | 8.99 | 5.78 |
| 2012 | 7.12 | 8.65 | 5.75 |
| 2011 | 9.78 | 14.47 | 6.34 |
| 2010 | 13.61 | 22.73 | 10.11 |
| 2009 | 21.96 | 32.02 | 10.29 |
| 2008 | 16.89 | 33.31 | 6.4 |
| 2007 | 25.98 | 36.91 | 15.65 |
| 2006 | 12.23 | 15.88 | 10.14 |
| 2005 | 9.84 | 12.97 | 6.74 |
| 2004 | 17.27 | 29.26 | 9.56 |
| 2003 | 18.76 | 21.86 | 15.96 |
| 2002 | 26.24 | 28.18 | 21.66 |
| 2001 | 41.21 | 57.23 | 23.42 |
| 2000 | 43.17 | 55.82 | 31.15 |
| 1999 | 40.90 | 68.43 | 34.44 |