| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.86 | 1.09 | 0.8 |
| 2024 | 0.7 | 1.01 | 0.44 |
| 2023 | 0.53 | 0.63 | 0.45 |
| 2022 | 0.67 | 0.91 | 0.56 |
| 2021 | 0.52 | 1.12 | 0.4 |
| 2020 | 0.49 | 0.65 | 0.37 |
| 2019 | 0.4 | 0.58 | 0.35 |
| 2018 | 0.5 | 0.69 | 0.39 |
| 2017 | 0.85 | 1.12 | 0.66 |
| 2016 | 1.17 | 2.16 | 0.86 |
| 2015 | 1.52 | 2.63 | 1.02 |
| 2014 | 0.89 | 1.32 | 0.54 |
| 2013 | 0.6 | 0.68 | 0.54 |
| 2012 | 0.68 | 0.83 | 0.5 |
| 2011 | 1.5 | 2.24 | 0.74 |
| 2010 | 1.82 | 2.46 | 1.44 |
| 2009 | 1.62 | 2.14 | 1.15 |
| 2008 | 2.2 | 5.87 | 0.63 |
| 2007 | 7.64 | 12.95 | 4.08 |
| 2006 | 4.29 | 5.27 | 3.07 |
| 2005 | 5.04 | 7.27 | 3.58 |
| 2004 | 9 | 17.87 | 4.79 |