| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.64 | 0.7 | 0.56 |
| 2024 | 0.63 | 0.76 | 0.51 |
| 2023 | 0.82 | 1.15 | 0.53 |
| 2022 | 0.51 | 0.74 | 0.35 |
| 2021 | 0.44 | 0.5 | 0.37 |
| 2020 | 0.97 | 1.92 | 0.49 |
| 2019 | 0.59 | 0.78 | 0.4 |
| 2018 | 0.49 | 0.72 | 0.3 |
| 2017 | 0.71 | 0.9 | 0.6 |
| 2016 | 0.78 | 0.92 | 0.67 |
| 2015 | 0.95 | 1.43 | 0.66 |
| 2014 | 0.6 | 0.81 | 0.49 |
| 2013 | 0.79 | 1.07 | 0.47 |
| 2012 | 0.49 | 0.69 | 0.38 |
| 2011 | 0.59 | 0.86 | 0.35 |
| 2010 | 1.05 | 1.76 | 0.72 |
| 2009 | 1.27 | 1.85 | 0.61 |
| 2008 | 1.32 | 3.32 | 0.4 |
| 2007 | 1.99 | 3.63 | 0.65 |
| 2006 | 0.54 | 0.69 | 0.41 |
| 2005 | 0.48 | 0.63 | 0.27 |
| 2004 | 0.74 | 1.72 | 0.35 |