| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.84 | 0.95 | 0.76 |
| 2024 | 1 | 1.26 | 0.81 |
| 2023 | 0.94 | 1.41 | 0.69 |
| 2022 | 1.08 | 1.48 | 0.76 |
| 2021 | 0.88 | 1.7 | 0.62 |
| 2020 | 0.56 | 0.8 | 0.44 |
| 2019 | 0.58 | 0.76 | 0.52 |
| 2018 | 0.82 | 1.29 | 0.56 |
| 2017 | 1.33 | 1.73 | 1.01 |
| 2016 | 1.46 | 2.05 | 0.88 |
| 2015 | 1.03 | 1.63 | 0.75 |
| 2014 | 0.69 | 1.09 | 0.53 |
| 2013 | 1 | 1.52 | 0.73 |
| 2012 | 1.61 | 2.29 | 1.08 |
| 2011 | 3.47 | 5.29 | 1.86 |
| 2010 | 5.37 | 7.91 | 3.83 |
| 2009 | 5.25 | 8.26 | 2.56 |
| 2008 | 5.48 | 10.95 | 1.5 |
| 2007 | 5.79 | 12.33 | 1.72 |
| 2006 | 1.49 | 1.95 | 1.24 |
| 2005 | 2.06 | 3.57 | 1.03 |
| 2004 | 2.46 | 3.76 | 1.93 |