| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.1 | 1.25 | 0.95 |
| 2024 | 0.89 | 1.11 | 0.7 |
| 2023 | 0.8 | 1.1 | 0.62 |
| 2022 | 0.59 | 0.8 | 0.42 |
| 2021 | 0.65 | 0.96 | 0.5 |
| 2020 | 0.76 | 0.94 | 0.59 |
| 2019 | 0.73 | 0.96 | 0.6 |
| 2018 | 0.9 | 1.3 | 0.6 |
| 2017 | 1.36 | 1.86 | 0.97 |
| 2016 | 1.43 | 1.63 | 1.07 |
| 2015 | 1.49 | 1.99 | 1 |
| 2014 | 0.63 | 1.24 | 0.5 |
| 2013 | 0.65 | 0.85 | 0.49 |
| 2012 | 0.86 | 1.08 | 0.61 |
| 2011 | 1.64 | 2.64 | 0.84 |
| 2010 | 1.53 | 2.34 | 0.92 |
| 2009 | 4.64 | 9.64 | 1.85 |
| 2008 | 2.89 | 5.27 | 1.67 |
| 2007 | 3.39 | 5.32 | 1.3 |
| 2006 | 1 | 1.47 | 0.58 |
| 2005 | 0.48 | 0.72 | 0.31 |
| 2004 | 0.65 | 1.41 | 0.39 |