| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.44 | 0.46 | 0.42 |
| 2024 | 0.46 | 0.55 | 0.39 |
| 2023 | 0.47 | 0.61 | 0.39 |
| 2022 | 0.59 | 0.82 | 0.48 |
| 2021 | 0.53 | 0.73 | 0.46 |
| 2020 | 0.54 | 0.63 | 0.49 |
| 2019 | 0.64 | 0.72 | 0.57 |
| 2018 | 0.67 | 0.85 | 0.53 |
| 2017 | 1.01 | 1.42 | 0.8 |
| 2016 | 1.1 | 1.7 | 0.92 |
| 2015 | 1.6 | 2.65 | 1.06 |
| 2014 | 0.86 | 1.33 | 0.76 |
| 2013 | 1.09 | 1.51 | 0.82 |
| 2012 | 1.4 | 1.77 | 1.22 |
| 2011 | 1.58 | 1.98 | 1.21 |
| 2010 | 1.81 | 2.2 | 1.41 |
| 2009 | 1.73 | 2.29 | 1.2 |
| 2008 | 2.16 | 4.46 | 1.04 |
| 2007 | 3.98 | 5.36 | 1.9 |
| 2006 | 1.46 | 1.92 | 1.3 |
| 2005 | 1.84 | 2.55 | 1.31 |
| 2004 | 2.71 | 4.67 | 1.6 |