| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.36 | 0.41 | 0.33 |
| 2024 | 0.33 | 0.38 | 0.28 |
| 2023 | 0.39 | 0.46 | 0.32 |
| 2022 | 0.4 | 0.58 | 0.34 |
| 2021 | 0.52 | 0.72 | 0.45 |
| 2020 | 0.44 | 0.5 | 0.38 |
| 2019 | 0.54 | 0.59 | 0.45 |
| 2018 | 0.64 | 0.84 | 0.51 |
| 2017 | 0.86 | 1 | 0.74 |
| 2016 | 0.85 | 1.06 | 0.63 |
| 2015 | 0.78 | 1.32 | 0.4 |
| 2014 | 0.34 | 0.45 | 0.28 |
| 2013 | 0.42 | 0.6 | 0.26 |
| 2012 | 0.44 | 0.5 | 0.37 |
| 2011 | 0.71 | 0.98 | 0.44 |
| 2010 | 1.13 | 1.78 | 0.81 |
| 2009 | 1.23 | 1.96 | 0.57 |
| 2008 | 1 | 2.32 | 0.4 |
| 2007 | 1.81 | 2.92 | 0.89 |
| 2006 | 0.87 | 1.09 | 0.66 |
| 2005 | 0.46 | 0.67 | 0.35 |
| 2004 | 0.67 | 1.24 | 0.37 |