| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.45 | 0.48 | 0.42 |
| 2024 | 0.49 | 0.57 | 0.41 |
| 2023 | 0.53 | 0.7 | 0.43 |
| 2022 | 0.44 | 0.53 | 0.4 |
| 2021 | 0.61 | 0.89 | 0.49 |
| 2020 | 0.68 | 1.13 | 0.43 |
| 2019 | 0.48 | 0.58 | 0.41 |
| 2018 | 0.56 | 0.78 | 0.43 |
| 2017 | 1.22 | 2.04 | 0.64 |
| 2016 | 1.13 | 1.55 | 0.99 |
| 2015 | 1.49 | 2.26 | 1.13 |
| 2014 | 1.08 | 1.42 | 0.88 |
| 2013 | 0.92 | 1.15 | 0.76 |
| 2012 | 0.86 | 0.97 | 0.72 |
| 2011 | 1.4 | 2.02 | 0.85 |
| 2010 | 2.23 | 2.79 | 1.77 |
| 2009 | 1.86 | 2.54 | 1.49 |
| 2008 | 1.85 | 2.72 | 1.24 |
| 2007 | 1.73 | 2.41 | 0.79 |
| 2006 | 0.66 | 1.15 | 0.39 |
| 2005 | 0.37 | 0.45 | 0.26 |
| 2004 | 0.48 | 0.88 | 0.3 |