| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.65 | 0.69 | 0.61 |
| 2024 | 0.58 | 0.74 | 0.45 |
| 2023 | 0.59 | 0.71 | 0.47 |
| 2022 | 0.61 | 0.84 | 0.44 |
| 2021 | 0.76 | 1.01 | 0.6 |
| 2020 | 0.98 | 1.39 | 0.74 |
| 2019 | 0.78 | 1.06 | 0.6 |
| 2018 | 0.96 | 1.34 | 0.7 |
| 2017 | 0.91 | 1.2 | 0.7 |
| 2016 | 0.76 | 0.93 | 0.6 |
| 2015 | 0.86 | 1.26 | 0.56 |
| 2014 | 0.65 | 0.86 | 0.55 |
| 2013 | 0.85 | 1.13 | 0.65 |
| 2012 | 0.91 | 1.1 | 0.7 |
| 2011 | 1.4 | 2.13 | 0.66 |
| 2010 | 1.18 | 1.61 | 0.84 |
| 2009 | 1.43 | 1.85 | 0.97 |
| 2008 | 2.36 | 4.52 | 0.77 |
| 2007 | 3.42 | 5.48 | 1.49 |
| 2006 | 1.4 | 1.74 | 1.1 |
| 2005 | 1.44 | 1.93 | 0.96 |
| 2004 | 3.13 | 5.83 | 1.44 |