| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.68 | 0.76 | 0.64 |
| 2024 | 0.74 | 0.84 | 0.64 |
| 2023 | 0.8 | 0.87 | 0.74 |
| 2022 | 0.91 | 1.25 | 0.75 |
| 2021 | 1.08 | 1.69 | 0.9 |
| 2020 | 1.04 | 1.25 | 0.85 |
| 2019 | 0.96 | 1.17 | 0.85 |
| 2018 | 1.24 | 1.74 | 0.87 |
| 2017 | 2.2 | 2.91 | 1.66 |
| 2016 | 3.2 | 4.44 | 2.88 |
| 2015 | 4.39 | 7.04 | 2.43 |
| 2014 | 2.51 | 2.95 | 1.9 |
| 2013 | 2.41 | 3.5 | 1.81 |
| 2012 | 5.9 | 10.63 | 2.24 |
| 2011 | 10.34 | 12.68 | 8.36 |
| 2010 | 12.52 | 15 | 10.51 |
| 2009 | 5.85 | 11 | 2.97 |
| 2008 | 4.94 | 12.16 | 1.77 |
| 2007 | 9.06 | 13.3 | 4.69 |
| 2006 | 3.47 | 4.51 | 2.9 |
| 2005 | 3.47 | 4.49 | 2.35 |