| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.5 | 0.64 | 0.39 |
| 2024 | 0.4 | 0.49 | 0.33 |
| 2023 | 0.52 | 0.61 | 0.42 |
| 2022 | 0.66 | 0.89 | 0.47 |
| 2021 | 0.93 | 1.25 | 0.78 |
| 2020 | 0.76 | 1.02 | 0.62 |
| 2019 | 1 | 1.57 | 0.69 |
| 2018 | 1.16 | 2.18 | 0.75 |
| 2017 | 1.01 | 1.05 | 0.88 |
| 2016 | 0.97 | 1.17 | 0.76 |
| 2015 | 1.3 | 1.91 | 0.93 |
| 2014 | 0.58 | 1.04 | 0.4 |
| 2013 | 0.53 | 0.69 | 0.43 |
| 2012 | 0.67 | 0.84 | 0.5 |
| 2011 | 1.22 | 1.83 | 0.71 |
| 2010 | 2.39 | 3.05 | 1.77 |
| 2009 | 1.79 | 2.82 | 0.94 |
| 2008 | 2.32 | 4.26 | 0.65 |
| 2007 | 3.31 | 5.56 | 1.22 |
| 2006 | 1.07 | 1.43 | 0.7 |
| 2005 | 0.59 | 0.72 | 0.41 |
| 2004 | 0.66 | 1.25 | 0.44 |