| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.23 | 1.29 | 1.19 |
| 2024 | 1.43 | 1.85 | 1.18 |
| 2023 | 1.43 | 1.72 | 1.19 |
| 2022 | 2.14 | 3.06 | 1.41 |
| 2021 | 1.76 | 2.67 | 1.16 |
| 2020 | 3.36 | 4.47 | 2.15 |
| 2019 | 2.77 | 4.18 | 1.29 |
| 2018 | 2.02 | 2.88 | 1.2 |
| 2017 | 3.02 | 3.56 | 2.67 |
| 2016 | 3.59 | 4.14 | 3.01 |
| 2015 | 4.52 | 7.85 | 2.95 |
| 2014 | 2.89 | 3.79 | 2.29 |
| 2013 | 2.66 | 3.39 | 2.24 |
| 2012 | 2.48 | 3.01 | 1.83 |
| 2011 | 3.76 | 5.42 | 2.63 |
| 2010 | 5.12 | 6.34 | 4.12 |
| 2009 | 3.95 | 5.57 | 2.85 |
| 2008 | 3.89 | 6.98 | 1.92 |
| 2007 | 5.1 | 6.99 | 4.77 |