| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.57 | 0.72 | 0.45 |
| 2024 | 0.38 | 0.8 | 0.27 |
| 2023 | 0.47 | 0.62 | 0.39 |
| 2022 | 0.38 | 0.57 | 0.27 |
| 2021 | 0.44 | 0.55 | 0.36 |
| 2020 | 1.15 | 2.08 | 0.53 |
| 2019 | 1.81 | 2.96 | 1.25 |
| 2018 | 3.06 | 4.32 | 1.61 |
| 2017 | 4.28 | 5.35 | 3.42 |
| 2016 | 5.19 | 6.46 | 3.73 |
| 2015 | 6.18 | 11.49 | 3.24 |
| 2014 | 3.81 | 5.21 | 2.81 |
| 2013 | 2.6 | 3.54 | 2 |
| 2012 | 2.37 | 2.92 | 1.91 |
| 2011 | 3.32 | 4.43 | 2.43 |
| 2010 | 4.32 | 6.35 | 2.91 |
| 2009 | 4.18 | 5.2 | 3.19 |
| 2008 | 4.2 | 7.1 | 2.03 |