| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2024 | 0.58 | 0.66 | 0.53 |
| 2023 | 0.53 | 0.6 | 0.5 |
| 2022 | 0.55 | 0.63 | 0.47 |
| 2021 | 0.67 | 0.82 | 0.57 |
| 2020 | 0.72 | 0.86 | 0.65 |
| 2019 | 0.88 | 0.98 | 0.81 |
| 2018 | 1.01 | 1.45 | 0.82 |
| 2017 | 0.99 | 1.13 | 0.88 |
| 2016 | 0.86 | 1.03 | 0.78 |
| 2015 | 1.18 | 1.45 | 0.88 |
| 2014 | 0.94 | 1.4 | 0.83 |
| 2013 | 1.15 | 1.4 | 0.95 |
| 2012 | 1.3 | 1.59 | 1.11 |
| 2011 | 1.69 | 2.03 | 1.45 |
| 2010 | 2.09 | 2.72 | 1.74 |
| 2009 | 2.46 | 3.13 | 1.8 |
| 2008 | 2.37 | 4.46 | 1.8 |