| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 2.1 | 2.4 | 1.79 |
| 2024 | 1.46 | 2.11 | 1.1 |
| 2023 | 1.59 | 1.83 | 1.4 |
| 2022 | 1.99 | 2.82 | 1.44 |
| 2021 | 2.15 | 3.2 | 1.66 |
| 2020 | 2.12 | 2.67 | 1.51 |
| 2019 | 1.75 | 2.42 | 1.39 |
| 2018 | 1.95 | 2.4 | 1.29 |
| 2017 | 3.17 | 5.12 | 2.21 |
| 2016 | 4.68 | 9.61 | 3.46 |
| 2015 | 6.65 | 13.73 | 4.43 |
| 2014 | 4.43 | 5.99 | 3.39 |
| 2013 | 4.04 | 4.92 | 3.29 |
| 2012 | 5.35 | 6.44 | 3.79 |
| 2011 | 7.97 | 11.25 | 5.32 |
| 2010 | 4.06 | 5.79 | 2.97 |
| 2009 | 3.74 | 5.2 | 1.71 |
| 2008 | 2.67 | 4.8 | 1.29 |