| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2020 | 8.08 | 8.74 | 7.34 |
| 2019 | 10.17 | 14.19 | 8.13 |
| 2018 | 11.86 | 15.35 | 9.69 |
| 2017 | 15.97 | 18.14 | 14.01 |
| 2016 | 15.67 | 20.97 | 13.24 |
| 2015 | 28.5 | 46.7 | 18.84 |
| 2014 | 11.17 | 22.05 | 9.16 |
| 2013 | 11 | 12.76 | 9.47 |
| 2012 | 10.99 | 14.18 | 8.96 |
| 2011 | 15.94 | 22.78 | 8.56 |
| 2010 | 26.12 | 34.75 | 18.36 |
| 2009 | 32.79 | 42.69 | 22.05 |
| 2008 | 26.75 | 42.17 | 14.95 |
| 2007 | 33.67 | 48.39 | 15.94 |
| 2006 | 12.8 | 15.76 | 10.61 |
| 2005 | 15.2 | 18.46 | 9.58 |
| 2004 | 23.57 | 30.41 | 18.04 |
| 2003 | 28.92 | 34.62 | 23.38 |
| 2002 | 37.4 | 43.11 | 29.68 |
| 2001 | 28.76 | 34.29 | 18.74 |
| 2000 | 27.62 | 33.54 | 21.88 |
| 1999 | 25.2 | 31.96 | 19.06 |