| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2024 | 1.61 | 2.09 | 1.22 |
| 2023 | 1.47 | 1.72 | 1.26 |
| 2022 | 1.5 | 2.25 | 1.11 |
| 2021 | 2.71 | 4.09 | 1.84 |
| 2020 | 2.55 | 3.04 | 2.1 |
| 2019 | 2.27 | 2.94 | 1.6 |
| 2018 | 1.77 | 2.1 | 1.59 |
| 2017 | 1.59 | 2.04 | 1.26 |
| 2016 | 1.09 | 1.43 | 0.9 |
| 2015 | 1.6 | 2.33 | 1.04 |
| 2014 | 1.32 | 1.79 | 1.18 |
| 2013 | 1.63 | 2.27 | 1.3 |
| 2012 | 2.04 | 2.73 | 1.41 |
| 2011 | 3.91 | 6.25 | 2.29 |
| 2010 | 4.85 | 6.69 | 3.42 |
| 2009 | 3.81 | 5.22 | 1.96 |
| 2008 | 2.8 | 5.35 | 1.41 |