| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.32 | 0.35 | 0.3 |
| 2024 | 0.27 | 0.44 | 0.2 |
| 2023 | 0.32 | 0.37 | 0.29 |
| 2022 | 0.38 | 0.49 | 0.31 |
| 2021 | 0.6 | 0.8 | 0.46 |
| 2020 | 0.64 | 0.74 | 0.58 |
| 2019 | 0.66 | 0.82 | 0.58 |
| 2018 | 0.96 | 1.51 | 0.6 |
| 2017 | 1.41 | 1.81 | 1.18 |
| 2016 | 1.27 | 1.57 | 1.03 |
| 2015 | 1.87 | 3.69 | 1.18 |
| 2014 | 1.18 | 1.49 | 0.94 |
| 2013 | 1.21 | 1.9 | 0.78 |
| 2012 | 0.79 | 1.2 | 0.59 |
| 2011 | 0.85 | 1.12 | 0.61 |
| 2010 | 1.03 | 1.52 | 0.75 |
| 2009 | 0.7 | 1.07 | 0.46 |
| 2008 | 1 | 2.14 | 0.38 |
| 2007 | 1.62 | 2.45 | 0.85 |
| 2006 | 0.81 | 1.02 | 0.64 |
| 2005 | 0.69 | 0.95 | 0.55 |
| 2004 | 0.84 | 1.47 | 0.43 |