| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.91 | 0.99 | 0.82 |
| 2024 | 0.94 | 1.13 | 0.79 |
| 2023 | 1.02 | 1.38 | 0.81 |
| 2022 | 0.82 | 1.13 | 0.59 |
| 2021 | 1.14 | 1.76 | 0.7 |
| 2020 | 1.59 | 2.48 | 1.18 |
| 2019 | 1.08 | 1.36 | 0.9 |
| 2018 | 1.78 | 2.85 | 0.98 |
| 2017 | 3.78 | 5.13 | 2.25 |
| 2016 | 4.53 | 6.01 | 2.95 |
| 2015 | 3.81 | 6.04 | 1.85 |
| 2014 | 1.73 | 2.49 | 1.35 |
| 2013 | 1.64 | 2.15 | 1.34 |
| 2012 | 1.59 | 2.06 | 1.25 |
| 2011 | 1.74 | 2.23 | 1.35 |
| 2010 | 1.68 | 2.23 | 1.33 |
| 2009 | 1.18 | 1.6 | 0.7 |
| 2008 | 0.96 | 1.63 | 0.52 |
| 2007 | 1.36 | 1.85 | 0.89 |
| 2006 | 0.89 | 1.02 | 0.66 |