| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.43 | 0.5 | 0.39 |
| 2024 | 0.37 | 0.58 | 0.3 |
| 2023 | 0.42 | 0.57 | 0.38 |
| 2022 | 0.39 | 0.49 | 0.32 |
| 2021 | 0.41 | 0.57 | 0.34 |
| 2020 | 0.56 | 0.77 | 0.49 |
| 2019 | 0.56 | 0.82 | 0.45 |
| 2018 | 0.65 | 0.89 | 0.42 |
| 2017 | 0.88 | 1.05 | 0.8 |
| 2016 | 0.93 | 1.22 | 0.63 |
| 2015 | 2.6 | 6.45 | 0.94 |
| 2014 | 1.66 | 3.02 | 1.07 |
| 2013 | 1.21 | 1.5 | 0.93 |
| 2012 | 1.66 | 2.26 | 1.03 |
| 2011 | 2.37 | 3.29 | 1.67 |
| 2010 | 2.84 | 3.8 | 2.15 |
| 2009 | 2.52 | 3.25 | 2.16 |
| 2008 | 2.82 | 4.96 | 1.47 |
| 2007 | 4.01 | 5.57 | 2.39 |
| 2006 | 2.08 | 2.6 | 1.48 |
| 2005 | 2.2 | 3.55 | 1.51 |
| 2004 | 3.74 | 6.06 | 2.15 |