| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.07 | 1.32 | 0.82 |
| 2024 | 1.01 | 1.29 | 0.87 |
| 2023 | 0.94 | 1.05 | 0.85 |
| 2022 | 0.85 | 0.97 | 0.75 |
| 2021 | 0.93 | 1.12 | 0.78 |
| 2020 | 1.13 | 1.41 | 1.02 |
| 2019 | 1.29 | 1.51 | 1.1 |
| 2018 | 1.31 | 1.51 | 1.18 |
| 2017 | 1.52 | 1.67 | 1.38 |
| 2016 | 1.49 | 1.72 | 1.31 |
| 2015 | 1.6 | 2.15 | 1.07 |
| 2014 | 0.93 | 1.65 | 0.71 |
| 2013 | 0.74 | 0.87 | 0.59 |
| 2012 | 0.87 | 1.02 | 0.7 |
| 2011 | 1.16 | 1.49 | 0.91 |
| 2010 | 1.43 | 1.77 | 1.15 |
| 2009 | 1.7 | 1.99 | 1.43 |
| 2008 | 2.22 | 4.33 | 1.37 |
| 2007 | 3.17 | 4.86 | 1.74 |
| 2006 | 1.41 | 1.72 | 1.05 |
| 2005 | 1.12 | 1.4 | 0.86 |
| 2004 | 1.53 | 2.18 | 1.07 |
| 2003 | 2.19 | 2.66 | 1.59 |
| 2002 | 2.36 | 2.62 | 2.11 |