| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.61 | 0.67 | 0.57 |
| 2024 | 0.57 | 0.65 | 0.49 |
| 2023 | 0.55 | 0.63 | 0.47 |
| 2022 | 0.54 | 0.62 | 0.44 |
| 2021 | 0.6 | 0.68 | 0.56 |
| 2020 | 0.73 | 0.91 | 0.62 |
| 2019 | 0.94 | 1.36 | 0.67 |
| 2018 | 0.73 | 0.92 | 0.6 |
| 2017 | 0.9 | 1.12 | 0.82 |
| 2016 | 0.89 | 1.22 | 0.8 |
| 2015 | 1.55 | 2.93 | 0.96 |
| 2014 | 0.8 | 1.27 | 0.67 |
| 2013 | 0.76 | 0.86 | 0.65 |
| 2012 | 0.85 | 0.97 | 0.72 |
| 2011 | 1.12 | 1.38 | 0.87 |
| 2010 | 1.47 | 1.84 | 1.21 |
| 2009 | 1.44 | 1.77 | 1.05 |
| 2008 | 1.73 | 3.12 | 0.95 |
| 2007 | 2.73 | 3.59 | 1.67 |
| 2006 | 1.49 | 2.01 | 1.2 |
| 2005 | 2.05 | 2.52 | 1.47 |
| 2004 | 2.16 | 2.46 | 1.86 |