| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.17 | 1.56 | 0.87 |
| 2024 | 0.78 | 1.44 | 0.54 |
| 2023 | 0.73 | 0.93 | 0.54 |
| 2022 | 0.58 | 0.7 | 0.5 |
| 2021 | 0.54 | 0.63 | 0.49 |
| 2020 | 0.62 | 0.83 | 0.45 |
| 2019 | 0.52 | 0.65 | 0.43 |
| 2018 | 0.58 | 0.8 | 0.44 |
| 2017 | 0.95 | 1.18 | 0.75 |
| 2016 | 1.07 | 1.42 | 0.92 |
| 2015 | 1.34 | 1.98 | 0.8 |
| 2014 | 0.66 | 0.89 | 0.54 |
| 2013 | 0.51 | 0.7 | 0.4 |
| 2012 | 0.56 | 0.7 | 0.42 |
| 2011 | 0.85 | 1.27 | 0.48 |
| 2010 | 1.44 | 2.2 | 1.02 |
| 2009 | 1.37 | 1.83 | 0.72 |
| 2008 | 1.31 | 2.81 | 0.57 |
| 2007 | 3.28 | 5.91 | 1.3 |
| 2006 | 1.28 | 1.91 | 0.96 |
| 2005 | 1.21 | 1.57 | 0.93 |
| 2004 | 1.54 | 2.3 | 0.71 |