| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2023 | 7.76 | 8.55 | 6.99 |
| 2022 | 8.14 | 11.64 | 5.46 |
| 2021 | 12.78 | 15.23 | 10.5 |
| 2020 | 10.15 | 12.8 | 8.18 |
| 2019 | 10.3 | 11.64 | 7.87 |
| 2018 | 10.04 | 12.8 | 7.96 |
| 2017 | 9.11 | 11.34 | 7.38 |
| 2016 | 7.32 | 7.98 | 6.13 |
| 2015 | 7.49 | 9.16 | 6.04 |
| 2014 | 5.02 | 7.21 | 4.55 |
| 2013 | 5.82 | 7.5 | 4.73 |
| 2012 | 6.35 | 8.38 | 4.99 |
| 2011 | 9.61 | 12.83 | 7.2 |
| 2010 | 15.64 | 22.98 | 10.63 |
| 2009 | 15.51 | 23.96 | 7.28 |
| 2008 | 21.53 | 50.31 | 7.03 |
| 2007 | 48.03 | 64.29 | 35.74 |
| 2006 | 25.36 | 46.45 | 19.52 |
| 2005 | 18.56 | 21.49 | 12.51 |
| 2004 | 24.56 | 34 | 18.45 |
| 2003 | 31.3 | 40.57 | 24.87 |