| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.48 | 0.51 | 0.44 |
| 2024 | 0.61 | 0.8 | 0.48 |
| 2023 | 0.49 | 0.64 | 0.39 |
| 2022 | 0.54 | 0.76 | 0.45 |
| 2021 | 0.55 | 0.95 | 0.33 |
| 2020 | 0.34 | 0.41 | 0.27 |
| 2019 | 0.39 | 0.61 | 0.25 |
| 2018 | 6.87 | 26.32 | 0.42 |
| 2017 | 4.55 | 5.95 | 3.61 |
| 2016 | 3.47 | 5.39 | 2.46 |
| 2015 | 3.57 | 5.83 | 2.46 |
| 2014 | 2.33 | 3.2 | 1.89 |
| 2013 | 2.73 | 3.6 | 2.18 |
| 2012 | 2.77 | 3.26 | 2.04 |
| 2011 | 3.6 | 4.58 | 3.02 |
| 2010 | 3.83 | 4.84 | 2.74 |
| 2009 | 4.08 | 4.9 | 2.3 |
| 2008 | 4.17 | 7.93 | 1.53 |
| 2007 | 5.77 | 8.38 | 3.35 |
| 2006 | 3.3 | 3.95 | 2.62 |
| 2005 | 3.48 | 5.32 | 2.7 |