| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.9 | 1.03 | 0.75 |
| 2024 | 0.75 | 1.38 | 0.3 |
| 2023 | 0.94 | 1.25 | 0.69 |
| 2022 | 0.72 | 0.93 | 0.52 |
| 2021 | 0.82 | 1.03 | 0.62 |
| 2020 | 0.71 | 0.96 | 0.5 |
| 2019 | 0.57 | 0.77 | 0.39 |
| 2018 | 0.48 | 0.7 | 0.3 |
| 2017 | 0.76 | 0.95 | 0.58 |
| 2016 | 0.99 | 1.23 | 0.75 |
| 2015 | 1.26 | 2.23 | 0.75 |
| 2014 | 1.06 | 1.8 | 0.71 |
| 2013 | 0.91 | 1.5 | 0.67 |
| 2012 | 0.57 | 0.77 | 0.38 |
| 2011 | 1.14 | 1.84 | 0.56 |
| 2010 | 1.99 | 3.12 | 1.26 |
| 2009 | 2.04 | 2.55 | 1.38 |
| 2008 | 3.46 | 8.12 | 1.2 |
| 2007 | 6.11 | 8.77 | 4.21 |
| 2006 | 3.86 | 5.79 | 2.54 |
| 2005 | 3.95 | 5.51 | 2.84 |
| 2004 | 6.61 | 15.23 | 3.68 |