| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 2.01 | 3.05 | 1.51 |
| 2024 | 1.6 | 2.05 | 1.21 |
| 2023 | 2.01 | 2.54 | 1.66 |
| 2022 | 2.36 | 3 | 1.85 |
| 2021 | 1.93 | 2.94 | 1.08 |
| 2020 | 1.6 | 1.93 | 1.27 |
| 2019 | 1.73 | 2.69 | 0.69 |
| 2018 | 1.78 | 2.7 | 0.73 |
| 2017 | 2.75 | 4.66 | 2.01 |
| 2016 | 3.65 | 4.72 | 2.59 |
| 2015 | 5.68 | 17.32 | 2.71 |
| 2014 | 4.53 | 8.45 | 2.79 |
| 2013 | 3.47 | 4.73 | 2.63 |
| 2012 | 3.85 | 5.23 | 2.81 |
| 2011 | 6.27 | 9.65 | 4.28 |
| 2010 | 4.3 | 6.93 | 3.07 |
| 2009 | 2.8 | 3.76 | 1.94 |
| 2008 | 3.19 | 8.36 | 1.12 |
| 2007 | 6.3 | 8.57 | 4.39 |