| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 2.41 | 2.87 | 2.2 |
| 2024 | 2.44 | 2.85 | 2.04 |
| 2023 | 3.66 | 4.99 | 2.29 |
| 2022 | 4.52 | 6.2 | 3.14 |
| 2021 | 4.08 | 5.49 | 3.15 |
| 2020 | 3.67 | 4.79 | 2.66 |
| 2019 | 2.37 | 3.05 | 1.84 |
| 2018 | 2.71 | 4.25 | 1.61 |
| 2017 | 3.49 | 4.85 | 2.59 |
| 2016 | 3.09 | 3.98 | 2.15 |
| 2015 | 3.34 | 5.55 | 2.05 |
| 2014 | 2.73 | 3.21 | 2.21 |
| 2013 | 2.17 | 2.64 | 1.56 |
| 2012 | 2.2 | 2.95 | 1.36 |
| 2011 | 4.15 | 6.23 | 2.03 |
| 2010 | 3.89 | 7.64 | 2.31 |
| 2009 | 2.13 | 2.74 | 1.19 |
| 2008 | 2.5 | 7.05 | 0.97 |
| 2007 | 5.21 | 6.53 | 3.87 |