| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.05 | 1.2 | 0.95 |
| 2024 | 1.04 | 1.44 | 0.67 |
| 2023 | 0.85 | 1.03 | 0.68 |
| 2022 | 0.64 | 0.77 | 0.57 |
| 2021 | 0.84 | 1.09 | 0.7 |
| 2020 | 1.03 | 1.45 | 0.71 |
| 2019 | 0.88 | 1.02 | 0.74 |
| 2018 | 0.78 | 0.97 | 0.68 |
| 2017 | 1.08 | 1.71 | 0.73 |
| 2016 | 1.14 | 1.9 | 0.55 |
| 2015 | 1.01 | 1.47 | 0.64 |
| 2014 | 0.8 | 1.09 | 0.71 |
| 2013 | 0.93 | 1.3 | 0.71 |
| 2012 | 1.34 | 1.74 | 1.12 |
| 2011 | 2.18 | 2.79 | 1.25 |
| 2010 | 2.49 | 3.34 | 1.75 |
| 2009 | 2.56 | 4.18 | 0.77 |
| 2008 | 1.83 | 4.98 | 0.49 |
| 2007 | 3.09 | 7.29 | 1.02 |
| 2006 | 1.06 | 1.67 | 0.54 |
| 2005 | 0.46 | 0.59 | 0.36 |
| 2004 | 0.69 | 1.36 | 0.37 |