| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.95 | 1.06 | 0.91 |
| 2024 | 0.85 | 1.13 | 0.57 |
| 2023 | 1.22 | 2.16 | 0.66 |
| 2022 | 0.52 | 1.78 | 0.41 |
| 2021 | 0.46 | 0.67 | 0.31 |
| 2020 | 0.37 | 0.59 | 0.29 |
| 2019 | 0.4 | 0.57 | 0.31 |
| 2018 | 0.58 | 0.75 | 0.46 |
| 2017 | 0.99 | 1.18 | 0.7 |
| 2016 | 1.13 | 1.39 | 0.93 |
| 2015 | 1.53 | 3.05 | 0.82 |
| 2014 | 0.63 | 1 | 0.44 |
| 2013 | 0.48 | 0.54 | 0.41 |
| 2012 | 0.49 | 0.6 | 0.4 |
| 2011 | 0.76 | 0.95 | 0.55 |
| 2010 | 1.18 | 1.47 | 0.85 |
| 2009 | 0.98 | 1.48 | 0.72 |
| 2008 | 1.43 | 2.67 | 0.67 |
| 2007 | 2.26 | 3.48 | 1.14 |
| 2006 | 1.2 | 1.42 | 0.99 |
| 2005 | 0.83 | 1.11 | 0.61 |
| 2004 | 1.86 | 4.55 | 0.97 |