| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.01 | 1.18 | 0.9 |
| 2024 | 0.86 | 1.13 | 0.75 |
| 2023 | 0.83 | 1.04 | 0.65 |
| 2022 | 0.77 | 1 | 0.64 |
| 2021 | 0.74 | 0.88 | 0.61 |
| 2020 | 1.13 | 1.8 | 0.86 |
| 2019 | 1.2 | 1.49 | 0.94 |
| 2018 | 1.38 | 2.34 | 0.93 |
| 2017 | 2.59 | 3.01 | 2.1 |
| 2016 | 1.77 | 2.85 | 1.09 |
| 2015 | 1.82 | 3.08 | 1.25 |
| 2014 | 1.27 | 1.61 | 1.03 |
| 2013 | 1.49 | 1.82 | 1.31 |
| 2012 | 1.68 | 2.03 | 1.39 |
| 2011 | 2.19 | 2.62 | 1.44 |
| 2010 | 1.82 | 3.01 | 1.17 |
| 2009 | 1.14 | 1.36 | 0.88 |
| 2008 | 1.33 | 2.26 | 0.69 |
| 2007 | 1.66 | 2.69 | 0.8 |
| 2006 | 0.72 | 0.9 | 0.42 |
| 2005 | 0.63 | 0.78 | 0.47 |
| 2004 | 0.72 | 1.25 | 0.5 |