| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.3 | 1.52 | 1.18 |
| 2024 | 1.32 | 1.9 | 0.86 |
| 2023 | 1.63 | 3.26 | 0.85 |
| 2022 | 1.9 | 2.43 | 1.54 |
| 2021 | 1.78 | 2.44 | 1.46 |
| 2020 | 1.47 | 2.01 | 1.23 |
| 2019 | 1.53 | 1.96 | 1.33 |
| 2018 | 1.82 | 2.38 | 1.34 |
| 2017 | 2.65 | 3.17 | 2.04 |
| 2016 | 3.13 | 4.39 | 2.56 |
| 2015 | 3.71 | 6.06 | 1.75 |
| 2014 | 1.77 | 2.14 | 1.47 |
| 2013 | 1.66 | 2.75 | 1.02 |
| 2012 | 2.59 | 3.72 | 0.85 |
| 2011 | 3.82 | 5.28 | 2.33 |
| 2010 | 4.77 | 6.66 | 3.04 |
| 2009 | 5.91 | 9.05 | 2.6 |
| 2008 | 5.99 | 11.12 | 2.04 |
| 2007 | 7.61 | 12.56 | 3.29 |
| 2006 | 3.77 | 6.69 | 3.07 |
| 2005 | 9.12 | 11.26 | 7.4 |
| 2004 | 10.3 | 19.07 | 6.68 |