| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.65 | 0.69 | 0.62 |
| 2024 | 0.76 | 1 | 0.62 |
| 2023 | 0.89 | 1.06 | 0.77 |
| 2022 | 0.7 | 0.94 | 0.55 |
| 2021 | 0.91 | 1.19 | 0.65 |
| 2020 | 0.96 | 1.18 | 0.6 |
| 2019 | 1.02 | 2 | 0.67 |
| 2018 | 1.76 | 2.25 | 1.29 |
| 2017 | 2.44 | 2.78 | 2.06 |
| 2016 | 2.56 | 3.39 | 1.78 |
| 2015 | 2.53 | 4.07 | 1.63 |
| 2014 | 1.44 | 2.08 | 1.11 |
| 2013 | 1.45 | 1.88 | 1.14 |
| 2012 | 1.09 | 1.43 | 0.91 |
| 2011 | 1.43 | 1.81 | 0.97 |
| 2010 | 1.86 | 2.36 | 1.42 |
| 2009 | 1.36 | 2.14 | 0.73 |
| 2008 | 1.17 | 1.82 | 0.61 |
| 2007 | 1.59 | 2.41 | 0.88 |
| 2006 | 0.91 | 1.01 | 0.79 |
| 2005 | 0.9 | 1.23 | 0.72 |