| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2026 | 1.33 | 1.58 | 1.14 |
| 2025 | 1.25 | 1.5 | 0.97 |
| 2024 | 1.05 | 1.45 | 0.77 |
| 2023 | 1.36 | 1.57 | 1.15 |
| 2022 | 1.33 | 1.87 | 1.06 |
| 2021 | 1.33 | 1.81 | 1.15 |
| 2020 | 1.32 | 1.78 | 1.06 |
| 2019 | 1.11 | 1.43 | 0.83 |
| 2018 | 1.56 | 2.16 | 0.99 |
| 2017 | 2.94 | 4.02 | 1.92 |
| 2016 | 3.53 | 4.32 | 2.81 |
| 2015 | 5.22 | 8.31 | 3.36 |
| 2014 | 5.91 | 9.69 | 3.82 |
| 2013 | 6.74 | 8.08 | 5.08 |
| 2012 | 5.45 | 6.55 | 4.66 |
| 2011 | 7.31 | 9.17 | 5.42 |
| 2010 | 7.51 | 9.76 | 5.39 |
| 2009 | 4.91 | 6.8 | 3.27 |
| 2008 | 4.15 | 7.15 | 2.5 |
| 2007 | 4.1 | 7.17 | 1.78 |
| 2006 | 2.08 | 3 | 1.47 |
| 2005 | 2.19 | 2.76 | 1.53 |