| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2026 | 0.67 | 0.71 | 0.65 |
| 2025 | 0.65 | 0.69 | 0.6 |
| 2024 | 0.56 | 0.68 | 0.51 |
| 2023 | 0.51 | 0.58 | 0.37 |
| 2022 | 0.36 | 0.4 | 0.29 |
| 2021 | 0.3 | 0.33 | 0.28 |
| 2020 | 0.32 | 0.46 | 0.17 |
| 2019 | 4.3 | 13.87 | 0.19 |
| 2018 | 7.45 | 14.15 | 4.96 |
| 2017 | 8.14 | 9.71 | 7.1 |
| 2016 | 7.05 | 10.17 | 4.54 |
| 2015 | 5.88 | 8.05 | 3.75 |
| 2014 | 4.39 | 6.47 | 2.43 |
| 2013 | 3.52 | 5.19 | 2.36 |
| 2012 | 3.68 | 4.51 | 2.82 |
| 2011 | 4.15 | 4.96 | 2.88 |
| 2010 | 4.83 | 5.98 | 3.92 |
| 2009 | 4.22 | 5.71 | 2.93 |
| 2008 | 5.75 | 12.32 | 1.77 |
| 2007 | 9.75 | 14.54 | 6.2 |
| 2006 | 7.3 | 9.18 | 5.57 |
| 2005 | 1.66 | 5.64 | 0.49 |
| 2004 | 0.94 | 1.78 | 0.57 |