| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.8 | 0.95 | 0.69 |
| 2024 | 0.71 | 0.94 | 0.59 |
| 2023 | 0.74 | 0.81 | 0.68 |
| 2022 | 0.8 | 0.88 | 0.71 |
| 2021 | 0.89 | 1.24 | 0.67 |
| 2020 | 0.72 | 0.83 | 0.64 |
| 2019 | 0.87 | 1.14 | 0.7 |
| 2018 | 1.14 | 1.45 | 0.84 |
| 2017 | 1.44 | 1.77 | 1.28 |
| 2016 | 1.33 | 1.8 | 1.2 |
| 2015 | 2.22 | 4.13 | 1.42 |
| 2014 | 0.96 | 1.81 | 0.77 |
| 2013 | 0.9 | 1.02 | 0.78 |
| 2012 | 1.28 | 3.04 | 0.77 |
| 2011 | 1.76 | 3.05 | 1.42 |
| 2010 | 1.91 | 2.71 | 1.53 |
| 2009 | 2.26 | 3.87 | 1.31 |
| 2008 | 2.82 | 6.36 | 0.94 |
| 2007 | 4.26 | 7.48 | 2.18 |
| 2006 | 1.27 | 2.02 | 0.99 |
| 2005 | 1.33 | 1.66 | 1.04 |