| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 6.98 | 9.3 | 6.03 |
| 2024 | 5.45 | 7.67 | 4.31 |
| 2023 | 6.55 | 8.41 | 5.28 |
| 2022 | 7.48 | 9.66 | 6.39 |
| 2021 | 8.19 | 9.78 | 7.44 |
| 2020 | 6.98 | 8.99 | 5.21 |
| 2019 | 5.66 | 6.79 | 4.93 |
| 2018 | 6.81 | 9.65 | 4.81 |
| 2017 | 9.79 | 10.99 | 8.79 |
| 2016 | 9.85 | 13.08 | 8.91 |
| 2015 | 12.87 | 18.39 | 8.8 |
| 2014 | 8.2 | 14.55 | 6.4 |
| 2013 | 10.41 | 15.24 | 8.07 |
| 2012 | 12.49 | 15.78 | 8.15 |
| 2011 | 17.58 | 22.06 | 12.04 |
| 2010 | 21.09 | 33.25 | 13.74 |
| 2009 | 24.11 | 36.02 | 11.98 |
| 2008 | 24.04 | 57.18 | 9.29 |
| 2007 | 40.63 | 69.27 | 10.79 |
| 2006 | 5.25 | 11.71 | 1.89 |
| 2005 | 2.17 | 2.71 | 1.52 |
| 2004 | 2.31 | 4.1 | 1.63 |