| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2026 | 0.69 | 0.87 | 0.59 |
| 2025 | 0.61 | 0.66 | 0.55 |
| 2024 | 0.67 | 0.87 | 0.52 |
| 2023 | 1.01 | 1.26 | 0.83 |
| 2022 | 0.73 | 0.96 | 0.51 |
| 2021 | 0.6 | 0.86 | 0.5 |
| 2020 | 0.58 | 0.66 | 0.52 |
| 2019 | 0.66 | 0.83 | 0.56 |
| 2018 | 0.84 | 1.13 | 0.63 |
| 2017 | 1.31 | 1.58 | 1.07 |
| 2016 | 1.15 | 1.36 | 0.94 |
| 2015 | 1.51 | 2.46 | 1.05 |
| 2014 | 0.93 | 1.3 | 0.73 |
| 2013 | 1.2 | 1.59 | 0.92 |
| 2012 | 1.35 | 1.73 | 1.18 |
| 2011 | 2.61 | 4.4 | 1.59 |
| 2010 | 2.59 | 3.09 | 2.13 |
| 2009 | 2.52 | 3.25 | 1.62 |
| 2008 | 2.77 | 5.88 | 1.4 |
| 2007 | 3.54 | 6.07 | 1.15 |
| 2006 | 1.09 | 1.33 | 0.93 |
| 2005 | 1.18 | 1.73 | 0.79 |
| 2004 | 1.93 | 3.39 | 1.19 |