| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2024 | 0.86 | 1.13 | 0.62 |
| 2023 | 1.04 | 1.37 | 0.77 |
| 2022 | 1.18 | 2.4 | 0.72 |
| 2021 | 2.28 | 3.53 | 1.57 |
| 2020 | 2.36 | 2.93 | 1.79 |
| 2019 | 1.31 | 2.05 | 0.78 |
| 2018 | 1.5 | 2.52 | 0.85 |
| 2017 | 4 | 5.23 | 2.2 |
| 2016 | 4.48 | 5.47 | 3.6 |
| 2015 | 6.49 | 10.03 | 4.12 |
| 2014 | 5.61 | 6.67 | 4.39 |
| 2013 | 6.1 | 7.42 | 4.79 |
| 2012 | 7.64 | 9.38 | 5.71 |
| 2011 | 9.17 | 10.69 | 8.11 |