| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.1 | 1.78 | 0.71 |
| 2024 | 0.65 | 1 | 0.5 |
| 2023 | 0.69 | 0.76 | 0.63 |
| 2022 | 0.71 | 0.85 | 0.62 |
| 2021 | 0.85 | 0.99 | 0.74 |
| 2020 | 0.74 | 0.88 | 0.61 |
| 2019 | 0.67 | 0.85 | 0.57 |
| 2018 | 0.93 | 1.42 | 0.58 |
| 2017 | 1.79 | 2.31 | 1.26 |
| 2016 | 2.51 | 3.08 | 2.14 |
| 2015 | 2.84 | 5.67 | 1.21 |
| 2014 | 1.12 | 1.77 | 0.74 |
| 2013 | 0.84 | 1.03 | 0.69 |
| 2012 | 0.93 | 1.23 | 0.7 |
| 2011 | 1.11 | 1.54 | 0.8 |
| 2010 | 1.41 | 1.9 | 1.06 |
| 2009 | 1.14 | 1.48 | 0.66 |
| 2008 | 2.6 | 6.95 | 0.56 |
| 2007 | 3.74 | 5.67 | 2.67 |