| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2026 | 0.73 | 0.81 | 0.65 |
| 2025 | 0.81 | 0.95 | 0.69 |
| 2024 | 0.62 | 0.91 | 0.39 |
| 2023 | 0.98 | 1.65 | 0.65 |
| 2022 | 1.27 | 2.16 | 0.75 |
| 2021 | 0.92 | 1.3 | 0.56 |
| 2020 | 0.59 | 1.03 | 0.38 |
| 2019 | 0.53 | 0.67 | 0.43 |
| 2018 | 0.86 | 1.27 | 0.54 |
| 2017 | 1.3 | 1.72 | 0.83 |
| 2016 | 0.97 | 1.4 | 0.61 |
| 2015 | 0.88 | 1.42 | 0.54 |
| 2014 | 0.43 | 0.69 | 0.31 |
| 2013 | 0.51 | 0.77 | 0.35 |
| 2012 | 0.8 | 1.06 | 0.56 |
| 2011 | 1.15 | 1.48 | 0.69 |
| 2010 | 1.43 | 2.39 | 0.96 |
| 2009 | 1.24 | 2.41 | 0.57 |
| 2008 | 1.23 | 2.84 | 0.4 |
| 2007 | 1.96 | 2.54 | 1.35 |