| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.8 | 0.92 | 0.68 |
| 2024 | 0.7 | 0.9 | 0.45 |
| 2023 | 0.49 | 0.58 | 0.42 |
| 2022 | 0.44 | 0.56 | 0.28 |
| 2021 | 0.51 | 0.69 | 0.41 |
| 2020 | 0.53 | 0.61 | 0.47 |
| 2019 | 0.56 | 0.72 | 0.48 |
| 2018 | 0.84 | 1.12 | 0.51 |
| 2017 | 1.25 | 1.6 | 0.86 |
| 2016 | 1.14 | 1.4 | 0.89 |
| 2015 | 1.31 | 2.01 | 0.95 |
| 2014 | 0.64 | 1.3 | 0.51 |
| 2013 | 0.69 | 0.9 | 0.55 |
| 2012 | 0.81 | 1.05 | 0.63 |
| 2011 | 1.39 | 2.23 | 0.71 |
| 2010 | 1.36 | 1.79 | 1.02 |
| 2009 | 1.1 | 1.58 | 0.49 |
| 2008 | 1.33 | 3.1 | 0.38 |
| 2007 | 2.32 | 3.38 | 1.59 |
| 2006 | 0.87 | 1.67 | 0.61 |
| 2005 | 0.55 | 0.71 | 0.4 |
| 2004 | 0.87 | 1.62 | 0.44 |