| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.65 | 0.74 | 0.52 |
| 2024 | 0.63 | 1.08 | 0.45 |
| 2023 | 0.84 | 0.99 | 0.7 |
| 2022 | 0.78 | 1.06 | 0.64 |
| 2021 | 0.96 | 1.33 | 0.77 |
| 2020 | 1.09 | 1.49 | 0.71 |
| 2019 | 1.05 | 1.49 | 0.8 |
| 2018 | 1.3 | 1.74 | 0.88 |
| 2017 | 2.45 | 4.29 | 1.48 |
| 2016 | 3.13 | 4.89 | 1.96 |
| 2015 | 2.63 | 4.4 | 1.55 |
| 2014 | 1.36 | 1.78 | 1.11 |
| 2013 | 1.28 | 1.73 | 1.01 |
| 2012 | 1.33 | 1.64 | 0.99 |
| 2011 | 18.06 | 84.97 | 1.32 |
| 2010 | 27.96 | 43.77 | 15.95 |
| 2009 | 9.77 | 16.14 | 4.77 |
| 2008 | 6.06 | 8.89 | 3.55 |
| 2007 | 5.29 | 7.71 | 2.94 |
| 2006 | 5.01 | 7.75 | 2.71 |
| 2005 | 7.69 | 8.66 | 5.07 |
| 2004 | 7.16 | 10.9 | 5.12 |