| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.81 | 0.88 | 0.73 |
| 2024 | 0.82 | 0.93 | 0.68 |
| 2023 | 0.94 | 1.14 | 0.82 |
| 2022 | 1.17 | 1.57 | 0.89 |
| 2021 | 2.02 | 2.88 | 1.36 |
| 2020 | 1.17 | 1.93 | 0.79 |
| 2019 | 1.11 | 1.67 | 0.94 |
| 2018 | 1.7 | 2.31 | 1.07 |
| 2017 | 2.57 | 3.67 | 2.02 |
| 2016 | 2.17 | 2.58 | 1.59 |
| 2015 | 2.61 | 3.76 | 1.84 |
| 2014 | 1.66 | 2.19 | 1.39 |
| 2013 | 1.55 | 1.79 | 1.27 |
| 2012 | 1.61 | 2.55 | 1.16 |
| 2011 | 2.77 | 4.03 | 1.79 |
| 2010 | 2.61 | 3.4 | 1.99 |
| 2009 | 2.47 | 3.8 | 1.23 |
| 2008 | 4.2 | 9.93 | 1.02 |
| 2007 | 4.22 | 7 | 1.89 |
| 2006 | 1.43 | 1.9 | 1.12 |
| 2005 | 1.57 | 1.89 | 1.06 |
| 2004 | 2.01 | 2.56 | 1.76 |