| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.4 | 0.58 | 0.31 |
| 2024 | 0.29 | 0.63 | 0.21 |
| 2023 | 0.32 | 0.42 | 0.28 |
| 2022 | 0.34 | 0.42 | 0.26 |
| 2021 | 0.45 | 0.71 | 0.3 |
| 2020 | 0.41 | 0.59 | 0.24 |
| 2019 | 2.67 | 7.39 | 0.31 |
| 2018 | 8.27 | 12.7 | 5.14 |
| 2017 | 11.1 | 13.31 | 8.84 |
| 2016 | 8.08 | 10.12 | 5.03 |
| 2015 | 6.05 | 11.31 | 3.19 |
| 2014 | 3.57 | 7.03 | 1.8 |
| 2013 | 3.61 | 6.34 | 1.86 |
| 2012 | 1.21 | 2.21 | 0.65 |
| 2011 | 1.36 | 1.77 | 0.69 |
| 2010 | 1.37 | 1.88 | 0.97 |
| 2009 | 1.45 | 2.16 | 0.51 |
| 2008 | 0.95 | 1.94 | 0.33 |
| 2007 | 1.77 | 2.88 | 0.98 |
| 2006 | 1.14 | 1.63 | 0.85 |
| 2005 | 0.96 | 1.33 | 0.66 |
| 2004 | 1.45 | 2.83 | 0.79 |