| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.84 | 1.28 | 0.7 |
| 2024 | 0.69 | 0.81 | 0.55 |
| 2023 | 0.91 | 1.2 | 0.69 |
| 2022 | 1.07 | 1.93 | 0.67 |
| 2021 | 0.87 | 1 | 0.77 |
| 2020 | 0.97 | 1.45 | 0.68 |
| 2019 | 0.98 | 1.5 | 0.76 |
| 2018 | 1.21 | 1.53 | 0.9 |
| 2017 | 1.38 | 1.69 | 1.2 |
| 2016 | 1.11 | 1.47 | 0.74 |
| 2015 | 1.41 | 2.19 | 0.79 |
| 2014 | 1.3 | 2.1 | 0.86 |
| 2013 | 0.66 | 0.99 | 0.39 |
| 2012 | 3.48 | 11.4 | 0.35 |
| 2011 | 4.96 | 10.45 | 3.8 |
| 2010 | 3.8 | 4.81 | 2.71 |
| 2009 | 5.06 | 6.81 | 3.74 |