| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.47 | 0.5 | 0.42 |
| 2024 | 0.42 | 0.67 | 0.31 |
| 2023 | 0.56 | 0.75 | 0.46 |
| 2022 | 0.71 | 0.93 | 0.58 |
| 2021 | 0.71 | 0.85 | 0.58 |
| 2020 | 0.81 | 1.02 | 0.65 |
| 2019 | 0.98 | 1.35 | 0.83 |
| 2018 | 1.33 | 2.33 | 0.65 |
| 2017 | 6.62 | 17.52 | 1.88 |
| 2016 | 3.47 | 6.2 | 2.7 |
| 2015 | 2.74 | 4.39 | 1.89 |
| 2014 | 2.34 | 2.79 | 2 |
| 2013 | 2.12 | 2.57 | 1.4 |
| 2012 | 1.71 | 2.14 | 1.17 |
| 2011 | 2.91 | 3.91 | 1.58 |
| 2010 | 3.4 | 4.22 | 2.57 |
| 2009 | 2.3 | 2.67 | 1.58 |
| 2008 | 2.72 | 5.3 | 1.31 |
| 2007 | 3.35 | 5.87 | 0.96 |
| 2006 | 0.78 | 1.05 | 0.58 |
| 2005 | 0.43 | 0.6 | 0.32 |
| 2004 | 0.65 | 1.22 | 0.38 |