| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.5 | 0.53 | 0.47 |
| 2024 | 0.55 | 0.62 | 0.48 |
| 2023 | 0.64 | 0.83 | 0.49 |
| 2022 | 0.6 | 0.73 | 0.48 |
| 2021 | 0.57 | 0.64 | 0.46 |
| 2020 | 0.6 | 0.88 | 0.46 |
| 2019 | 0.95 | 1.13 | 0.77 |
| 2018 | 1.06 | 1.13 | 0.94 |
| 2017 | 1.18 | 1.33 | 1.03 |
| 2016 | 1.34 | 1.6 | 1.27 |
| 2015 | 1.38 | 1.77 | 1.15 |
| 2014 | 1.24 | 1.5 | 1.14 |
| 2013 | 1.11 | 1.29 | 0.99 |
| 2012 | 0.93 | 1.01 | 0.83 |
| 2011 | 1.11 | 1.42 | 0.82 |
| 2010 | 1.38 | 1.63 | 1.17 |
| 2009 | 1.17 | 1.51 | 0.89 |
| 2008 | 0.99 | 1.93 | 0.59 |
| 2007 | 1.93 | 3.1 | 1.11 |
| 2006 | 1.17 | 1.41 | 0.98 |
| 2005 | 0.59 | 1.1 | 0.38 |
| 2004 | 0.54 | 0.88 | 0.36 |