| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.56 | 0.65 | 0.5 |
| 2024 | 0.49 | 0.67 | 0.34 |
| 2023 | 0.56 | 0.66 | 0.42 |
| 2022 | 0.57 | 0.74 | 0.41 |
| 2021 | 0.49 | 0.73 | 0.39 |
| 2020 | 0.5 | 0.62 | 0.39 |
| 2019 | 0.59 | 0.85 | 0.44 |
| 2018 | 0.56 | 0.73 | 0.43 |
| 2017 | 0.89 | 1.14 | 0.71 |
| 2016 | 1.09 | 1.32 | 0.87 |
| 2015 | 1.79 | 3.73 | 0.93 |
| 2014 | 1.55 | 1.94 | 1.31 |
| 2013 | 1.8 | 2.15 | 1.45 |
| 2012 | 1.96 | 2.46 | 1.62 |
| 2011 | 3.83 | 6.69 | 1.86 |
| 2010 | 4 | 6.36 | 2.77 |
| 2009 | 2.54 | 3.16 | 2 |
| 2008 | 2.76 | 5.65 | 1.5 |
| 2007 | 5.45 | 7.51 | 3.45 |
| 2006 | 2.44 | 3.54 | 1.72 |
| 2005 | 1.9 | 2.73 | 1.38 |
| 2004 | 4.89 | 9.39 | 2.17 |