| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.75 | 0.84 | 0.61 |
| 2024 | 0.73 | 1.19 | 0.41 |
| 2023 | 0.76 | 0.9 | 0.63 |
| 2022 | 0.87 | 1.18 | 0.56 |
| 2021 | 0.71 | 1 | 0.54 |
| 2020 | 0.96 | 1.31 | 0.7 |
| 2019 | 0.76 | 1.07 | 0.61 |
| 2018 | 1.17 | 1.85 | 0.6 |
| 2017 | 2.22 | 2.93 | 1.69 |
| 2016 | 4.04 | 4.95 | 2.77 |
| 2015 | 5.2 | 11.41 | 1.82 |
| 2014 | 2.1 | 2.92 | 1.59 |
| 2013 | 2.47 | 3.51 | 1.63 |
| 2012 | 2.04 | 2.88 | 1.32 |
| 2011 | 3.79 | 5.61 | 2.49 |
| 2010 | 3.7 | 5.98 | 2.39 |
| 2009 | 1.94 | 3.55 | 0.82 |
| 2008 | 1.48 | 3 | 0.56 |
| 2007 | 2.26 | 2.94 | 1.76 |