| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.7 | 0.94 | 0.53 |
| 2024 | 0.61 | 0.74 | 0.42 |
| 2023 | 0.5 | 0.57 | 0.41 |
| 2022 | 0.52 | 0.81 | 0.35 |
| 2021 | 0.55 | 0.8 | 0.36 |
| 2020 | 0.37 | 0.44 | 0.31 |
| 2019 | 0.46 | 0.57 | 0.37 |
| 2018 | 0.57 | 0.79 | 0.41 |
| 2017 | 0.59 | 0.75 | 0.45 |
| 2016 | 0.57 | 0.73 | 0.47 |
| 2015 | 0.79 | 1.31 | 0.4 |
| 2014 | 0.69 | 0.97 | 0.5 |
| 2013 | 0.95 | 1.69 | 0.55 |
| 2012 | 1.49 | 1.86 | 1.19 |
| 2011 | 2.43 | 3.66 | 1.21 |
| 2010 | 2.56 | 3.87 | 1.49 |
| 2009 | 2.05 | 3.61 | 0.64 |
| 2008 | 1.92 | 5.3 | 0.49 |
| 2007 | 3.71 | 8.08 | 1.15 |
| 2006 | 0.95 | 1.37 | 0.75 |
| 2005 | 0.98 | 1.38 | 0.79 |
| 2004 | 1.42 | 2.4 | 0.9 |