| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.48 | 0.52 | 0.45 |
| 2024 | 0.46 | 0.57 | 0.4 |
| 2023 | 0.5 | 0.56 | 0.43 |
| 2022 | 0.55 | 0.72 | 0.44 |
| 2021 | 0.73 | 1.04 | 0.56 |
| 2020 | 0.8 | 1.21 | 0.54 |
| 2019 | 0.59 | 0.71 | 0.48 |
| 2018 | 0.62 | 0.91 | 0.43 |
| 2017 | 0.85 | 1.13 | 0.68 |
| 2016 | 0.83 | 1.22 | 0.5 |
| 2015 | 1.06 | 1.7 | 0.73 |
| 2014 | 1.21 | 1.78 | 0.93 |
| 2013 | 1.45 | 2.08 | 0.88 |
| 2012 | 0.82 | 0.92 | 0.74 |
| 2011 | 0.98 | 1.31 | 0.78 |
| 2010 | 1.23 | 1.51 | 0.9 |
| 2009 | 0.97 | 1.33 | 0.57 |
| 2008 | 1.02 | 1.89 | 0.42 |
| 2007 | 1.56 | 2.37 | 0.95 |
| 2006 | 0.97 | 1.24 | 0.66 |
| 2005 | 0.7 | 1.03 | 0.55 |
| 2004 | 0.94 | 1.57 | 0.62 |