| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.89 | 1.02 | 0.79 |
| 2024 | 0.84 | 1.02 | 0.7 |
| 2023 | 1.11 | 1.66 | 0.86 |
| 2022 | 0.94 | 1.14 | 0.8 |
| 2021 | 0.79 | 0.91 | 0.7 |
| 2020 | 0.94 | 1.18 | 0.78 |
| 2019 | 1.49 | 2.26 | 1.06 |
| 2018 | 1.99 | 2.74 | 1.32 |
| 2017 | 3.24 | 4.21 | 2.59 |
| 2016 | 3.14 | 3.88 | 2.58 |
| 2015 | 3.9 | 5.8 | 2.37 |
| 2014 | 2.86 | 4.37 | 2.32 |
| 2013 | 4.28 | 6.84 | 2.49 |
| 2012 | 5.74 | 7.18 | 4.62 |
| 2011 | 6.4 | 10.63 | 4.9 |
| 2010 | 6.53 | 11.63 | 3.47 |
| 2009 | 3.5 | 4.87 | 2.08 |
| 2008 | 3.15 | 5.9 | 1.51 |
| 2007 | 5.57 | 7.02 | 4.43 |