| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.05 | 1.1 | 0.92 |
| 2024 | 0.89 | 1.13 | 0.72 |
| 2023 | 1.14 | 1.54 | 0.91 |
| 2022 | 1.22 | 1.59 | 0.82 |
| 2021 | 1.03 | 1.51 | 0.6 |
| 2020 | 0.95 | 1.37 | 0.72 |
| 2019 | 0.84 | 1.15 | 0.47 |
| 2018 | 0.9 | 1.36 | 0.58 |
| 2017 | 1.64 | 2.07 | 1.27 |
| 2016 | 2.16 | 2.75 | 1.85 |
| 2015 | 3.43 | 5.71 | 1.78 |
| 2014 | 2.14 | 2.87 | 1.66 |
| 2013 | 1.81 | 2.57 | 0.9 |
| 2012 | 0.99 | 1.25 | 0.79 |
| 2011 | 1.27 | 1.58 | 1.01 |
| 2010 | 1.56 | 1.76 | 1.31 |
| 2009 | 1.12 | 1.86 | 0.82 |
| 2008 | 1.27 | 2.22 | 0.62 |
| 2007 | 1.48 | 2.48 | 0.57 |
| 2006 | 0.66 | 0.91 | 0.51 |
| 2005 | 0.89 | 1.25 | 0.63 |
| 2004 | 1.57 | 3.01 | 0.88 |