| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.33 | 1.58 | 1.11 |
| 2024 | 1.2 | 1.48 | 0.9 |
| 2023 | 1.08 | 1.49 | 0.75 |
| 2022 | 0.81 | 1.15 | 0.62 |
| 2021 | 1.11 | 1.49 | 0.88 |
| 2020 | 1.69 | 2.79 | 1.26 |
| 2019 | 1.26 | 1.54 | 1.03 |
| 2018 | 1.2 | 1.86 | 0.84 |
| 2017 | 2.19 | 3.02 | 1.63 |
| 2016 | 3.12 | 4.01 | 2.25 |
| 2015 | 4.59 | 5.01 | 3.77 |
| 2014 | 4.16 | 6.39 | 3.19 |
| 2013 | 9.2 | 14.63 | 4.63 |
| 2012 | 8.36 | 10.38 | 6.51 |
| 2011 | 15.76 | 28.21 | 7.33 |
| 2010 | 17.2 | 29.41 | 11.69 |
| 2009 | 8.67 | 14.39 | 4.51 |
| 2008 | 7.92 | 14.6 | 3.59 |