| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.83 | 0.88 | 0.76 |
| 2024 | 0.76 | 1.02 | 0.64 |
| 2023 | 0.9 | 1.01 | 0.83 |
| 2022 | 0.92 | 1.16 | 0.73 |
| 2021 | 0.88 | 1.05 | 0.79 |
| 2020 | 0.86 | 0.99 | 0.65 |
| 2019 | 0.87 | 1.18 | 0.72 |
| 2018 | 1.1 | 1.56 | 0.79 |
| 2017 | 1.74 | 2.23 | 1.32 |
| 2016 | 1.56 | 2.05 | 1.22 |
| 2015 | 1.57 | 2.53 | 0.99 |
| 2014 | 0.99 | 1.33 | 0.6 |
| 2013 | 0.6 | 0.87 | 0.46 |
| 2012 | 0.75 | 1.08 | 0.53 |
| 2011 | 1.44 | 1.92 | 0.85 |
| 2010 | 1.29 | 1.7 | 1.01 |
| 2009 | 1.09 | 1.47 | 0.73 |
| 2008 | 1.35 | 2.53 | 0.59 |
| 2007 | 2 | 3.12 | 1.15 |
| 2006 | 1.15 | 1.47 | 0.8 |
| 2005 | 0.94 | 2.03 | 0.7 |
| 2004 | 3.48 | 4.35 | 2.03 |