| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 2.78 | 3 | 2.52 |
| 2024 | 2.56 | 3.68 | 2.13 |
| 2023 | 2.36 | 3.6 | 1.81 |
| 2022 | 1.99 | 2.31 | 1.68 |
| 2021 | 2.29 | 2.68 | 2.06 |
| 2020 | 2.47 | 3.21 | 2.02 |
| 2019 | 2.27 | 2.87 | 1.49 |
| 2018 | 1.59 | 2.29 | 1.16 |
| 2017 | 2.52 | 3.15 | 2.1 |
| 2016 | 3.19 | 4.52 | 2.38 |
| 2015 | 6.06 | 9.16 | 3.12 |
| 2014 | 5.76 | 8.9 | 3.3 |
| 2013 | 4.27 | 5.23 | 3.7 |
| 2012 | 4.82 | 5.94 | 3.69 |
| 2011 | 7.2 | 9.7 | 4.67 |
| 2010 | 11.48 | 16.79 | 8.35 |
| 2009 | 16.47 | 21.88 | 13.45 |
| 2008 | 17.34 | 26.82 | 9.99 |