| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2021 | 5.68 | 7.07 | 4.66 |
| 2020 | 4.81 | 5.85 | 3.98 |
| 2019 | 5.65 | 7.38 | 4.83 |
| 2018 | 6.72 | 10.17 | 4.79 |
| 2017 | 10.24 | 12.31 | 7.35 |
| 2016 | 12.01 | 14.93 | 10.99 |
| 2015 | 14.66 | 21.78 | 11.63 |
| 2014 | 8.29 | 13.89 | 6.12 |
| 2013 | 10.65 | 16.81 | 7.21 |
| 2012 | 13.62 | 16.65 | 12.31 |
| 2011 | 14.31 | 16.54 | 11.92 |
| 2010 | 26.74 | 53.04 | 12.99 |
| 2009 | 47.07 | 68.52 | 20.94 |
| 2008 | 50.63 | 142.8 | 18.23 |
| 2007 | 93.3 | 167.89 | 37.34 |
| 2006 | 34.04 | 53.84 | 24.2 |
| 2005 | 30.89 | 39.25 | 22.79 |
| 2004 | 24.3 | 34.03 | 18.07 |
| 2003 | 21.54 | 27.28 | 17.62 |
| 2002 | 31.83 | 34.72 | 26.97 |
| 2001 | 57.57 | 80.25 | 38.17 |
| 2000 | 78.38 | 92.24 | 55.28 |
| 1999 | 68.5 | 119.59 | 33.4 |
| 1998 | 36.66 | 49.82 | 20.38 |