| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.6 | 0.71 | 0.52 |
| 2024 | 0.64 | 1.04 | 0.44 |
| 2023 | 1.08 | 1.43 | 0.76 |
| 2022 | 1.12 | 1.47 | 0.76 |
| 2021 | 0.94 | 1.21 | 0.73 |
| 2020 | 2.2 | 3.47 | 1.08 |
| 2019 | 1.74 | 2.45 | 1.02 |
| 2018 | 1.51 | 2.69 | 0.95 |
| 2017 | 1.56 | 2.01 | 1.25 |
| 2016 | 2.94 | 5.49 | 1.78 |
| 2015 | 3.57 | 6.93 | 1.3 |
| 2014 | 1.36 | 1.73 | 1.14 |
| 2013 | 1.66 | 2.91 | 1.17 |
| 2012 | 2.13 | 2.79 | 1.69 |
| 2011 | 3.14 | 4.61 | 1.82 |
| 2010 | 4.32 | 7.1 | 2.75 |
| 2009 | 6.6 | 9.01 | 3.82 |