| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.65 | 0.69 | 0.61 |
| 2024 | 0.62 | 0.74 | 0.44 |
| 2023 | 0.81 | 1.25 | 0.68 |
| 2022 | 0.83 | 1.51 | 0.62 |
| 2021 | 0.83 | 1.17 | 0.61 |
| 2020 | 0.83 | 1.34 | 0.63 |
| 2019 | 0.64 | 0.78 | 0.53 |
| 2018 | 0.8 | 1.15 | 0.53 |
| 2017 | 1.7 | 2.41 | 0.98 |
| 2016 | 2.09 | 2.47 | 1.78 |
| 2015 | 2.26 | 3.61 | 1.5 |
| 2014 | 1.8 | 2.96 | 1.27 |
| 2013 | 1.48 | 1.79 | 0.98 |
| 2012 | 1.1 | 1.36 | 0.83 |
| 2011 | 2.02 | 3.04 | 1.12 |
| 2010 | 2.24 | 3.02 | 1.62 |
| 2009 | 1.72 | 2.32 | 1.1 |
| 2008 | 1.74 | 3.38 | 0.81 |
| 2007 | 2.99 | 4.92 | 1.65 |
| 2006 | 1.57 | 1.96 | 1.33 |
| 2005 | 2.32 | 2.87 | 1.8 |
| 2004 | 4.31 | 8.27 | 2.31 |