| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.8 | 1.06 | 0.58 |
| 2024 | 0.53 | 0.78 | 0.38 |
| 2023 | 0.39 | 0.6 | 0.3 |
| 2022 | 0.37 | 0.52 | 0.3 |
| 2021 | 0.49 | 0.66 | 0.38 |
| 2020 | 0.66 | 0.87 | 0.49 |
| 2019 | 0.71 | 0.85 | 0.56 |
| 2018 | 0.87 | 1.24 | 0.5 |
| 2017 | 1.19 | 1.61 | 1.04 |
| 2016 | 1.23 | 1.46 | 0.89 |
| 2015 | 1.3 | 2.31 | 0.66 |
| 2014 | 0.59 | 0.69 | 0.51 |
| 2013 | 0.66 | 0.79 | 0.56 |
| 2012 | 0.8 | 1.13 | 0.58 |
| 2011 | 1.36 | 1.87 | 0.81 |
| 2010 | 1.42 | 2.01 | 1.07 |
| 2009 | 4.46 | 14.12 | 1.55 |
| 2008 | 2.26 | 3.39 | 1.05 |
| 2007 | 2 | 2.75 | 0.72 |
| 2006 | 0.76 | 0.95 | 0.65 |