| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2026 | 0.96 | 1.01 | 0.94 |
| 2025 | 0.99 | 1.32 | 0.86 |
| 2024 | 0.82 | 1.14 | 0.66 |
| 2023 | 0.9 | 0.96 | 0.83 |
| 2022 | 0.88 | 1.11 | 0.8 |
| 2021 | 0.79 | 0.89 | 0.72 |
| 2020 | 0.94 | 1.49 | 0.78 |
| 2019 | 0.89 | 1.48 | 0.74 |
| 2018 | 0.97 | 1.29 | 0.71 |
| 2017 | 1.48 | 1.95 | 1.19 |
| 2016 | 1.62 | 2.05 | 1.41 |
| 2015 | 2.17 | 3.39 | 1.14 |
| 2014 | 1.74 | 3.21 | 1.22 |
| 2013 | 1.13 | 1.51 | 0.85 |
| 2012 | 1.33 | 1.66 | 0.93 |
| 2011 | 2.59 | 5.61 | 1.37 |
| 2010 | 3.68 | 5.42 | 2.84 |
| 2009 | 2.47 | 3.23 | 1.72 |
| 2008 | 2.81 | 4.61 | 1.27 |
| 2007 | 3.51 | 5.57 | 1.45 |
| 2006 | 1.42 | 1.85 | 1.1 |
| 2005 | 1.4 | 1.84 | 1.02 |
| 2004 | 2.29 | 2.99 | 1.63 |
| 2003 | 3.1 | 3.79 | 2.26 |
| 2002 | 3.64 | 4.04 | 2.75 |
| 2001 | 4.5 | 5.24 | 3.28 |