| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2026 | 3.8 | 4.8 | 3.2 |
| 2025 | 3.28 | 3.96 | 2.93 |
| 2024 | 3.19 | 4.81 | 2.5 |
| 2023 | 3.26 | 3.82 | 2.72 |
| 2022 | 3.7 | 5.5 | 2.7 |
| 2021 | 3.62 | 5.83 | 2.54 |
| 2020 | 3.37 | 4.66 | 2.6 |
| 2019 | 4.21 | 6.7 | 3.05 |
| 2018 | 5.01 | 8.36 | 2.78 |
| 2017 | 9.27 | 11.97 | 7.45 |
| 2016 | 10.94 | 15.52 | 7.83 |
| 2015 | 13.43 | 18.27 | 6.77 |
| 2014 | 5.57 | 7.58 | 4.47 |
| 2013 | 5.06 | 5.97 | 4.11 |
| 2012 | 5.88 | 7.56 | 4.2 |
| 2011 | 8.35 | 10.74 | 5.31 |
| 2010 | 11.41 | 17.29 | 7.88 |
| 2009 | 12.29 | 17.19 | 3.67 |
| 2008 | 8.74 | 16.99 | 2.86 |
| 2007 | 12.54 | 16.83 | 9.35 |
| 2006 | 5.79 | 10.07 | 2.8 |
| 2005 | 3.39 | 4.6 | 2.86 |
| 2004 | 4.44 | 7.42 | 3.12 |