| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.34 | 0.39 | 0.29 |
| 2024 | 0.33 | 0.47 | 0.22 |
| 2023 | 0.43 | 0.48 | 0.34 |
| 2022 | 0.52 | 0.8 | 0.42 |
| 2021 | 0.58 | 0.71 | 0.49 |
| 2020 | 0.74 | 1.03 | 0.59 |
| 2019 | 0.79 | 1.07 | 0.67 |
| 2018 | 1.13 | 1.59 | 0.76 |
| 2017 | 1.46 | 1.78 | 1.26 |
| 2016 | 1.42 | 1.79 | 1.26 |
| 2015 | 1.82 | 2.99 | 1.22 |
| 2014 | 0.95 | 1.39 | 0.67 |
| 2013 | 1.33 | 1.95 | 0.88 |
| 2012 | 0.68 | 0.99 | 0.41 |
| 2011 | 0.76 | 1.36 | 0.42 |
| 2010 | 1.45 | 2.13 | 0.99 |
| 2009 | 1.76 | 2.7 | 0.56 |
| 2008 | 1.19 | 2.56 | 0.5 |
| 2007 | 2.04 | 3.39 | 0.89 |
| 2006 | 0.8 | 1 | 0.69 |
| 2005 | 0.8 | 1.02 | 0.64 |
| 2004 | 1.33 | 2.49 | 0.75 |