| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.95 | 1.02 | 0.86 |
| 2024 | 0.92 | 1.16 | 0.7 |
| 2023 | 0.92 | 1.12 | 0.76 |
| 2022 | 0.89 | 1.05 | 0.75 |
| 2021 | 1.3 | 1.72 | 0.92 |
| 2020 | 1.87 | 2.17 | 1.55 |
| 2019 | 1.67 | 2.24 | 1.19 |
| 2018 | 2.25 | 3.78 | 1.17 |
| 2017 | 2.86 | 3.47 | 2.14 |
| 2016 | 2.01 | 2.53 | 1.23 |
| 2015 | 1.39 | 2.15 | 0.87 |
| 2014 | 1.04 | 1.3 | 0.86 |
| 2013 | 1.09 | 1.37 | 0.86 |
| 2012 | 0.9 | 1.18 | 0.69 |
| 2011 | 1.59 | 2.21 | 0.97 |
| 2010 | 1.46 | 2.28 | 1.03 |
| 2009 | 0.81 | 1.32 | 0.58 |
| 2008 | 1.05 | 1.9 | 0.33 |
| 2007 | 1.11 | 1.49 | 0.69 |
| 2006 | 0.64 | 0.81 | 0.53 |
| 2005 | 0.66 | 0.91 | 0.49 |