| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.98 | 1.08 | 0.91 |
| 2024 | 0.97 | 1.42 | 0.65 |
| 2023 | 1.31 | 1.55 | 1.11 |
| 2022 | 1.19 | 1.62 | 0.85 |
| 2021 | 1.48 | 2.44 | 0.85 |
| 2020 | 0.86 | 1 | 0.67 |
| 2019 | 0.79 | 1.3 | 0.67 |
| 2018 | 0.94 | 1.25 | 0.67 |
| 2017 | 1.7 | 2.39 | 1.15 |
| 2016 | 1.38 | 1.69 | 1.05 |
| 2015 | 1.51 | 2.29 | 1.07 |
| 2014 | 0.76 | 1.15 | 0.55 |
| 2013 | 0.72 | 0.96 | 0.52 |
| 2012 | 0.82 | 1.06 | 0.64 |
| 2011 | 1.7 | 3.2 | 0.88 |
| 2010 | 2.17 | 2.82 | 1.42 |
| 2009 | 1.79 | 2.29 | 1.16 |
| 2008 | 2.46 | 4.59 | 0.97 |
| 2007 | 4.31 | 8.24 | 2.63 |
| 2006 | 1.63 | 2.86 | 1.03 |
| 2005 | 1.24 | 1.44 | 0.97 |