| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.79 | 0.9 | 0.74 |
| 2024 | 0.9 | 1.11 | 0.67 |
| 2023 | 0.52 | 0.66 | 0.42 |
| 2022 | 0.5 | 0.61 | 0.39 |
| 2021 | 0.54 | 0.73 | 0.37 |
| 2020 | 0.43 | 0.56 | 0.38 |
| 2019 | 0.6 | 0.73 | 0.51 |
| 2018 | 0.78 | 1.06 | 0.62 |
| 2017 | 1.2 | 1.5 | 0.94 |
| 2016 | 1.24 | 1.67 | 0.96 |
| 2015 | 1.47 | 2.56 | 1.05 |
| 2014 | 0.77 | 1.31 | 0.66 |
| 2013 | 0.95 | 1.27 | 0.73 |
| 2012 | 1.23 | 1.58 | 0.96 |
| 2011 | 1.76 | 2.3 | 1.3 |
| 2010 | 2.52 | 3.96 | 1.82 |
| 2009 | 3.46 | 4.4 | 2.24 |