| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.98 | 1.52 | 0.58 |
| 2024 | 0.57 | 0.78 | 0.39 |
| 2023 | 0.61 | 0.71 | 0.53 |
| 2022 | 0.62 | 1.05 | 0.45 |
| 2021 | 0.53 | 0.69 | 0.42 |
| 2020 | 0.77 | 1.04 | 0.53 |
| 2019 | 1.38 | 2.38 | 0.86 |
| 2018 | 2.1 | 3.76 | 1.28 |
| 2017 | 4.37 | 7.75 | 2.64 |
| 2016 | 2.34 | 3.41 | 1.17 |
| 2015 | 1.65 | 2.79 | 0.97 |
| 2014 | 1.12 | 1.45 | 0.77 |
| 2013 | 0.83 | 1 | 0.69 |
| 2012 | 0.94 | 1.39 | 0.61 |
| 2011 | 4.04 | 9.39 | 0.95 |
| 2010 | 6.14 | 7.47 | 4.72 |
| 2009 | 4.69 | 6.6 | 2.36 |
| 2008 | 3.38 | 4.46 | 2.18 |
| 2007 | 2.89 | 4.57 | 1.48 |
| 2006 | 1.14 | 1.62 | 0.72 |
| 2005 | 0.67 | 0.89 | 0.49 |
| 2004 | 1.2 | 2.16 | 0.67 |