| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.75 | 1.02 | 0.64 |
| 2024 | 0.65 | 0.89 | 0.51 |
| 2023 | 0.7 | 0.87 | 0.6 |
| 2022 | 0.75 | 0.98 | 0.63 |
| 2021 | 0.7 | 0.82 | 0.64 |
| 2020 | 0.78 | 0.98 | 0.69 |
| 2019 | 0.77 | 0.98 | 0.65 |
| 2018 | 0.87 | 1.1 | 0.71 |
| 2017 | 1.46 | 1.91 | 1.06 |
| 2016 | 1.99 | 2.67 | 1.67 |
| 2015 | 2.31 | 4.38 | 1.42 |
| 2014 | 1.51 | 1.87 | 1.24 |
| 2013 | 1.29 | 1.47 | 1.17 |
| 2012 | 0.94 | 1.2 | 0.73 |
| 2011 | 1.03 | 1.32 | 0.72 |
| 2010 | 1.02 | 1.28 | 0.79 |
| 2009 | 0.87 | 1.09 | 0.62 |
| 2008 | 0.85 | 1.48 | 0.48 |
| 2007 | 1.02 | 1.57 | 0.56 |
| 2006 | 0.58 | 0.68 | 0.47 |
| 2005 | 0.5 | 0.66 | 0.37 |
| 2004 | 0.65 | 1.29 | 0.43 |