| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.47 | 0.52 | 0.42 |
| 2024 | 0.51 | 0.6 | 0.42 |
| 2023 | 0.45 | 0.54 | 0.35 |
| 2022 | 0.54 | 0.68 | 0.47 |
| 2021 | 0.63 | 0.94 | 0.47 |
| 2020 | 0.42 | 0.56 | 0.34 |
| 2019 | 0.46 | 0.57 | 0.38 |
| 2018 | 0.49 | 0.59 | 0.42 |
| 2017 | 0.8 | 1.24 | 0.5 |
| 2016 | 0.73 | 1.13 | 0.49 |
| 2015 | 0.62 | 0.94 | 0.46 |
| 2014 | 0.39 | 0.64 | 0.3 |
| 2013 | 0.52 | 0.7 | 0.36 |
| 2012 | 0.68 | 0.86 | 0.54 |
| 2011 | 1.3 | 1.88 | 0.7 |
| 2010 | 1.99 | 3.56 | 1.22 |
| 2009 | 2.49 | 3.86 | 0.81 |
| 2008 | 2.87 | 6.18 | 0.58 |
| 2007 | 3.95 | 7.4 | 1.5 |
| 2006 | 1.31 | 1.66 | 1.16 |
| 2005 | 1.75 | 2.91 | 1.33 |