| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.71 | 0.81 | 0.64 |
| 2024 | 0.86 | 1.09 | 0.62 |
| 2023 | 1.12 | 1.37 | 0.92 |
| 2022 | 0.82 | 1.25 | 0.55 |
| 2021 | 0.6 | 0.7 | 0.5 |
| 2020 | 0.71 | 0.89 | 0.58 |
| 2019 | 1.08 | 1.68 | 0.78 |
| 2018 | 1.24 | 1.61 | 0.98 |
| 2017 | 1.31 | 1.49 | 1.2 |
| 2016 | 1.42 | 2.4 | 1.02 |
| 2015 | 1.8 | 2.8 | 1.28 |
| 2014 | 0.97 | 1.89 | 0.76 |
| 2013 | 0.91 | 1.13 | 0.7 |
| 2012 | 1.05 | 1.3 | 0.84 |
| 2011 | 1.44 | 1.81 | 0.98 |
| 2010 | 2.03 | 3.14 | 1.54 |
| 2009 | 3.2 | 4.34 | 1.73 |
| 2008 | 4.66 | 9.41 | 1.28 |
| 2007 | 6.68 | 10.99 | 2.5 |
| 2006 | 1.97 | 3.23 | 1.36 |
| 2005 | 1.44 | 1.94 | 1.07 |