| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2021 | 15.15 | 17.44 | 13.51 |
| 2020 | 23.66 | 41.41 | 13.28 |
| 2019 | 33.44 | 49.62 | 17.42 |
| 2018 | 13.66 | 17.7 | 11.34 |
| 2017 | 13.81 | 14.75 | 12.8 |
| 2016 | 15.01 | 17.81 | 13.16 |
| 2015 | 18.38 | 24.23 | 12.74 |
| 2014 | 13.36 | 15.78 | 10.63 |
| 2013 | 10.9 | 16.13 | 5.62 |
| 2012 | 10.31 | 17.14 | 5.48 |
| 2011 | 20.48 | 44.06 | 8.46 |
| 2010 | 26.2 | 46.17 | 14.07 |
| 2009 | 27 | 39.02 | 15.08 |
| 2008 | 26.03 | 52.65 | 12.68 |
| 2007 | 42.97 | 70.24 | 23.02 |
| 2006 | 15.75 | 23.65 | 12.6 |
| 2005 | 14.24 | 17.76 | 11.41 |
| 2004 | 18.31 | 24.44 | 13.96 |
| 2003 | 22.21 | 27.47 | 17.72 |
| 2002 | 33.18 | 36.65 | 27.83 |
| 2001 | 55.25 | 65.82 | 42.97 |
| 2000 | 42.16 | 54.84 | 34.01 |
| 1999 | 36.92 | 46.49 | 28.4 |