| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.86 | 0.91 | 0.78 |
| 2024 | 1.09 | 1.48 | 0.85 |
| 2023 | 0.98 | 1.19 | 0.76 |
| 2022 | 1.2 | 1.53 | 1 |
| 2021 | 1.22 | 1.77 | 1 |
| 2020 | 1.05 | 1.32 | 0.83 |
| 2019 | 1.36 | 1.75 | 1.06 |
| 2018 | 3.89 | 14.08 | 1.17 |
| 2017 | 2.84 | 3.93 | 1.93 |
| 2016 | 2.59 | 3.56 | 2.07 |
| 2015 | 3.17 | 5.15 | 2.07 |
| 2014 | 2.24 | 3.11 | 1.86 |
| 2013 | 2.51 | 4.88 | 1.68 |
| 2012 | 3.51 | 4.18 | 2.76 |
| 2011 | 4.15 | 5.3 | 3.59 |
| 2010 | 4.46 | 5.6 | 3.2 |
| 2009 | 4.26 | 5.42 | 2.12 |
| 2008 | 3.08 | 5.3 | 1.29 |
| 2007 | 3.39 | 4.95 | 1.73 |
| 2006 | 1.65 | 1.97 | 1.33 |
| 2005 | 1.64 | 2.31 | 1.22 |