| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.01 | 1.11 | 0.89 |
| 2024 | 0.95 | 1.23 | 0.68 |
| 2023 | 1.02 | 1.4 | 0.77 |
| 2022 | 1.56 | 2.22 | 1.13 |
| 2021 | 1.07 | 2.38 | 0.48 |
| 2020 | 0.57 | 0.69 | 0.44 |
| 2019 | 0.43 | 0.57 | 0.32 |
| 2018 | 0.39 | 0.74 | 0.25 |
| 2017 | 0.86 | 1.09 | 0.67 |
| 2016 | 0.88 | 1.16 | 0.67 |
| 2015 | 1.11 | 1.43 | 0.65 |
| 2014 | 0.56 | 0.82 | 0.36 |
| 2013 | 0.42 | 0.52 | 0.35 |
| 2012 | 0.63 | 1.04 | 0.4 |
| 2011 | 1.1 | 1.4 | 0.76 |
| 2010 | 1.15 | 1.55 | 0.81 |
| 2009 | 1.17 | 1.61 | 0.89 |
| 2008 | 3.42 | 7.43 | 0.74 |
| 2007 | 3.84 | 6.15 | 1.67 |
| 2006 | 1.45 | 1.95 | 0.88 |
| 2005 | 1.05 | 1.45 | 0.81 |
| 2004 | 1.57 | 2.88 | 0.85 |