| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.97 | 1.23 | 0.87 |
| 2024 | 0.82 | 1.1 | 0.64 |
| 2023 | 0.92 | 1.16 | 0.78 |
| 2022 | 0.94 | 1.5 | 0.78 |
| 2021 | 0.89 | 1.05 | 0.78 |
| 2020 | 0.94 | 1.18 | 0.78 |
| 2019 | 0.93 | 1.2 | 0.62 |
| 2018 | 1 | 1.31 | 0.78 |
| 2017 | 1.1 | 1.43 | 0.95 |
| 2016 | 1.12 | 1.36 | 0.96 |
| 2015 | 1.22 | 1.91 | 0.76 |
| 2014 | 0.98 | 1.53 | 0.56 |
| 2013 | 0.63 | 0.87 | 0.49 |
| 2012 | 0.66 | 0.83 | 0.52 |
| 2011 | 1.04 | 1.6 | 0.6 |
| 2010 | 1.24 | 1.82 | 0.87 |
| 2009 | 1.57 | 1.93 | 0.96 |
| 2008 | 1.13 | 1.73 | 0.55 |
| 2007 | 1.29 | 1.98 | 0.58 |
| 2006 | 0.55 | 0.7 | 0.39 |
| 2005 | 0.51 | 0.71 | 0.41 |
| 2004 | 0.74 | 1.33 | 0.47 |