| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.53 | 0.56 | 0.5 |
| 2024 | 0.51 | 0.68 | 0.4 |
| 2023 | 0.61 | 0.68 | 0.56 |
| 2022 | 0.74 | 0.93 | 0.56 |
| 2021 | 0.53 | 0.83 | 0.43 |
| 2020 | 0.71 | 0.9 | 0.53 |
| 2019 | 0.67 | 0.9 | 0.52 |
| 2018 | 0.95 | 1.42 | 0.52 |
| 2017 | 1.66 | 2.71 | 1.27 |
| 2016 | 1.24 | 1.47 | 0.94 |
| 2015 | 1.18 | 1.89 | 0.75 |
| 2014 | 0.73 | 1.11 | 0.63 |
| 2013 | 0.94 | 1.46 | 0.66 |
| 2012 | 1.31 | 1.78 | 0.93 |
| 2011 | 2.22 | 3.61 | 1.21 |
| 2010 | 2.86 | 3.9 | 2.23 |
| 2009 | 3.67 | 4.57 | 2.66 |
| 2008 | 3.56 | 7.41 | 1.33 |
| 2007 | 4.44 | 7.03 | 1.82 |
| 2006 | 1.63 | 2.02 | 1.29 |
| 2005 | 1.24 | 1.77 | 0.94 |
| 2004 | 2.57 | 5.04 | 1.2 |