| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.73 | 0.78 | 0.69 |
| 2024 | 0.8 | 0.97 | 0.6 |
| 2023 | 1.01 | 1.39 | 0.69 |
| 2022 | 1.15 | 1.56 | 0.73 |
| 2021 | 1.1 | 1.6 | 0.8 |
| 2020 | 0.91 | 1.05 | 0.76 |
| 2019 | 0.98 | 1.58 | 0.75 |
| 2018 | 0.72 | 0.88 | 0.61 |
| 2017 | 0.78 | 0.9 | 0.67 |
| 2016 | 0.67 | 0.83 | 0.59 |
| 2015 | 1.13 | 1.97 | 0.7 |
| 2014 | 0.65 | 1.02 | 0.53 |
| 2013 | 0.63 | 0.73 | 0.53 |
| 2012 | 0.85 | 1.18 | 0.53 |
| 2011 | 1.36 | 1.98 | 1.05 |
| 2010 | 1.57 | 2.21 | 1.19 |
| 2009 | 1.16 | 1.51 | 0.65 |
| 2008 | 3.29 | 13.39 | 0.35 |
| 2007 | 5.97 | 12.42 | 2.72 |
| 2006 | 2.35 | 2.83 | 1.87 |
| 2005 | 1.51 | 2.38 | 1.04 |
| 2004 | 1.94 | 3.56 | 1.22 |