| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.61 | 0.75 | 0.52 |
| 2024 | 0.53 | 0.76 | 0.37 |
| 2023 | 0.67 | 0.83 | 0.55 |
| 2022 | 0.88 | 1.08 | 0.75 |
| 2021 | 0.8 | 0.94 | 0.7 |
| 2020 | 0.8 | 0.92 | 0.71 |
| 2019 | 0.9 | 1.25 | 0.77 |
| 2018 | 0.99 | 1.44 | 0.73 |
| 2017 | 1.62 | 1.99 | 1.41 |
| 2016 | 1.77 | 2.06 | 1.46 |
| 2015 | 2.16 | 3.32 | 1.41 |
| 2014 | 1.36 | 2.07 | 1.09 |
| 2013 | 1.2 | 1.42 | 0.92 |
| 2012 | 1.43 | 1.98 | 0.77 |
| 2011 | 2.2 | 2.61 | 1.72 |
| 2010 | 1.77 | 2.42 | 1.34 |
| 2009 | 1.47 | 2.17 | 0.57 |
| 2008 | 0.94 | 1.96 | 0.43 |
| 2007 | 1.68 | 2.53 | 0.9 |
| 2006 | 1.2 | 1.62 | 0.89 |
| 2005 | 1.45 | 1.91 | 1.27 |