| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.37 | 0.37 | 0.36 |
| 2024 | 0.4 | 0.5 | 0.32 |
| 2023 | 0.6 | 0.73 | 0.48 |
| 2022 | 0.89 | 1.31 | 0.62 |
| 2021 | 0.83 | 1.28 | 0.64 |
| 2020 | 0.89 | 1.23 | 0.63 |
| 2019 | 0.65 | 0.92 | 0.58 |
| 2018 | 0.76 | 1.02 | 0.6 |
| 2017 | 1.1 | 1.36 | 0.93 |
| 2016 | 1.3 | 1.72 | 1.13 |
| 2015 | 1.7 | 3.54 | 0.9 |
| 2014 | 0.83 | 1.01 | 0.7 |
| 2013 | 0.87 | 1.1 | 0.7 |
| 2012 | 1.1 | 1.28 | 0.83 |
| 2011 | 0.95 | 1.26 | 0.73 |
| 2010 | 0.87 | 1.23 | 0.66 |
| 2009 | 0.93 | 1.21 | 0.77 |
| 2008 | 0.94 | 1.81 | 0.48 |