| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.1 | 1.25 | 0.92 |
| 2024 | 0.92 | 1.58 | 0.63 |
| 2023 | 0.83 | 0.97 | 0.71 |
| 2022 | 0.94 | 1.56 | 0.68 |
| 2021 | 1.16 | 1.91 | 0.71 |
| 2020 | 0.74 | 0.94 | 0.57 |
| 2019 | 0.66 | 0.87 | 0.55 |
| 2018 | 0.69 | 0.92 | 0.47 |
| 2017 | 1.03 | 1.3 | 0.82 |
| 2016 | 0.98 | 1.3 | 0.84 |
| 2015 | 1.26 | 2.22 | 0.79 |
| 2014 | 0.64 | 0.89 | 0.48 |
| 2013 | 0.56 | 0.64 | 0.47 |
| 2012 | 0.69 | 0.88 | 0.56 |
| 2011 | 1.19 | 1.71 | 0.71 |
| 2010 | 1.72 | 2.35 | 1.33 |
| 2009 | 1.7 | 2.5 | 0.88 |
| 2008 | 1.69 | 3.58 | 0.67 |
| 2007 | 2.64 | 3.96 | 1.04 |
| 2006 | 0.99 | 1.17 | 0.89 |
| 2005 | 1.13 | 1.62 | 0.84 |
| 2004 | 1.91 | 3.41 | 1.11 |