| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.46 | 0.49 | 0.43 |
| 2024 | 0.45 | 0.55 | 0.4 |
| 2023 | 0.52 | 0.63 | 0.43 |
| 2022 | 0.54 | 0.66 | 0.47 |
| 2021 | 0.58 | 0.81 | 0.5 |
| 2020 | 0.54 | 0.69 | 0.46 |
| 2019 | 0.72 | 1.08 | 0.58 |
| 2018 | 0.78 | 1.24 | 0.62 |
| 2017 | 1.05 | 1.34 | 0.84 |
| 2016 | 0.95 | 1.22 | 0.57 |
| 2015 | 2.11 | 8.41 | 0.79 |
| 2014 | 1.16 | 2.21 | 0.81 |
| 2013 | 1.38 | 2 | 0.96 |
| 2012 | 1.4 | 1.55 | 1.22 |
| 2011 | 2.25 | 3.55 | 1.39 |
| 2010 | 2.52 | 3.62 | 1.92 |
| 2009 | 1.88 | 3.14 | 0.83 |
| 2008 | 1.3 | 2.64 | 0.64 |
| 2007 | 2.33 | 3.71 | 0.92 |
| 2006 | 0.94 | 1.18 | 0.71 |
| 2005 | 0.5 | 0.72 | 0.34 |
| 2004 | 0.9 | 1.52 | 0.56 |