| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.56 | 1.85 | 1.36 |
| 2024 | 1.38 | 1.91 | 0.9 |
| 2023 | 1.37 | 1.57 | 1.17 |
| 2022 | 1.4 | 1.85 | 0.97 |
| 2021 | 1.19 | 2.3 | 0.86 |
| 2020 | 0.94 | 1.09 | 0.83 |
| 2019 | 1.17 | 1.46 | 0.8 |
| 2018 | 1.29 | 1.86 | 0.89 |
| 2017 | 1.98 | 2.64 | 1.58 |
| 2016 | 2.36 | 3.02 | 2.02 |
| 2015 | 3.66 | 5.94 | 2 |
| 2014 | 2.28 | 3.16 | 1.78 |
| 2013 | 2.11 | 2.58 | 1.74 |
| 2012 | 2.62 | 4.36 | 1.37 |
| 2011 | 6.34 | 9.32 | 3.94 |
| 2010 | 6.29 | 9.44 | 4.68 |
| 2009 | 4.88 | 6.85 | 2.92 |
| 2008 | 4.89 | 8.23 | 2.23 |
| 2007 | 5.88 | 7.18 | 4.92 |