| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2020 | 15.84 | 16.44 | 14.03 |
| 2019 | 19.06 | 23.96 | 14.75 |
| 2018 | 31.73 | 39.74 | 18.02 |
| 2017 | 28.98 | 33.15 | 25.6 |
| 2016 | 27.58 | 31.71 | 24.85 |
| 2015 | 33.6 | 41.73 | 28.25 |
| 2014 | 36.54 | 43.02 | 30.11 |
| 2013 | 35 | 40.93 | 30.85 |
| 2012 | 31.03 | 38.1 | 25.34 |
| 2011 | 32.66 | 38.69 | 27.08 |
| 2010 | 30.8 | 40.37 | 22.58 |
| 2009 | 30.6 | 35.89 | 24.44 |
| 2008 | 32.3 | 52.55 | 15.57 |
| 2007 | 50.84 | 86.38 | 27.79 |
| 2006 | 36.01 | 51.57 | 25.21 |
| 2005 | 49.35 | 65.11 | 40.84 |
| 2004 | 66.14 | 103.89 | 45.71 |
| 2003 | 77.12 | 91.23 | 59.34 |
| 2002 | 83.03 | 95.73 | 70.61 |
| 2001 | 86.15 | 99.53 | 70.09 |