| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 5.6 | 6.42 | 5.02 |
| 2024 | 4.52 | 7.48 | 3.27 |
| 2023 | 4.48 | 6.06 | 3.75 |
| 2022 | 3.84 | 5.54 | 2.79 |
| 2021 | 4.64 | 5.66 | 3.96 |
| 2020 | 7 | 10.99 | 5.28 |
| 2019 | 5.08 | 8.93 | 2.74 |
| 2018 | 4.38 | 8.77 | 2 |
| 2017 | 11.38 | 17.23 | 8.17 |
| 2016 | 10.89 | 12.92 | 8.49 |
| 2015 | 12.02 | 24.85 | 7.11 |
| 2014 | 6.34 | 8.28 | 4.98 |
| 2013 | 6.96 | 9.47 | 5.59 |
| 2012 | 8.54 | 10.2 | 5.76 |
| 2011 | 10.8 | 11.87 | 10.2 |
| 2010 | 15.52 | 20.51 | 10.97 |
| 2009 | 11.45 | 21 | 5.01 |
| 2008 | 5.37 | 8.46 | 3.22 |
| 2007 | 3.38 | 7.2 | 1.19 |
| 2006 | 1.28 | 1.57 | 0.99 |
| 2005 | 0.82 | 1.44 | 0.5 |
| 2004 | 1.02 | 1.97 | 0.61 |