| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.63 | 0.67 | 0.6 |
| 2024 | 0.71 | 0.8 | 0.62 |
| 2023 | 0.88 | 1.34 | 0.53 |
| 2022 | 1.31 | 1.69 | 0.99 |
| 2021 | 1.29 | 2.2 | 0.88 |
| 2020 | 0.77 | 0.96 | 0.58 |
| 2019 | 0.69 | 0.85 | 0.61 |
| 2018 | 0.73 | 0.91 | 0.61 |
| 2017 | 0.91 | 1.05 | 0.78 |
| 2016 | 0.78 | 0.98 | 0.7 |
| 2015 | 1.21 | 1.78 | 0.86 |
| 2014 | 0.99 | 1.38 | 0.83 |
| 2013 | 1.07 | 1.57 | 0.82 |
| 2012 | 0.99 | 1.34 | 0.73 |
| 2011 | 1.89 | 2.62 | 1.12 |
| 2010 | 2.29 | 3.13 | 1.6 |
| 2009 | 2.67 | 3.22 | 2.24 |
| 2008 | 2.24 | 3.64 | 1.58 |
| 2007 | 2.17 | 3.63 | 1.22 |
| 2006 | 0.97 | 1.25 | 0.65 |
| 2005 | 0.64 | 0.82 | 0.44 |
| 2004 | 0.93 | 1.5 | 0.61 |