| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.52 | 0.56 | 0.46 |
| 2024 | 0.51 | 0.59 | 0.43 |
| 2023 | 0.54 | 0.65 | 0.46 |
| 2022 | 0.66 | 0.88 | 0.5 |
| 2021 | 1.24 | 1.79 | 0.77 |
| 2020 | 0.67 | 1.2 | 0.45 |
| 2019 | 0.6 | 0.91 | 0.51 |
| 2018 | 0.88 | 1.19 | 0.58 |
| 2017 | 1.19 | 1.58 | 0.89 |
| 2016 | 0.99 | 1.18 | 0.73 |
| 2015 | 1.25 | 1.79 | 0.89 |
| 2014 | 0.81 | 1.09 | 0.67 |
| 2013 | 0.77 | 0.9 | 0.62 |
| 2012 | 0.78 | 1.09 | 0.6 |
| 2011 | 1.47 | 2.24 | 0.76 |
| 2010 | 1.73 | 2.49 | 1.29 |
| 2009 | 1.52 | 2.79 | 0.58 |
| 2008 | 2.05 | 4.39 | 0.48 |
| 2007 | 1.98 | 3.1 | 1 |
| 2006 | 0.8 | 1.01 | 0.63 |
| 2005 | 0.94 | 1.38 | 0.59 |
| 2004 | 1.47 | 2.65 | 0.92 |