| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.47 | 0.56 | 0.4 |
| 2024 | 0.51 | 0.63 | 0.41 |
| 2023 | 0.54 | 0.7 | 0.44 |
| 2022 | 0.55 | 0.74 | 0.44 |
| 2021 | 0.46 | 0.82 | 0.32 |
| 2020 | 0.45 | 0.58 | 0.38 |
| 2019 | 0.59 | 0.69 | 0.5 |
| 2018 | 0.66 | 0.76 | 0.56 |
| 2017 | 0.88 | 1.05 | 0.66 |
| 2016 | 0.92 | 1.03 | 0.79 |
| 2015 | 1.1 | 1.6 | 0.8 |
| 2014 | 0.62 | 1.03 | 0.49 |
| 2013 | 0.63 | 0.76 | 0.52 |
| 2012 | 0.63 | 0.75 | 0.53 |
| 2011 | 0.65 | 0.86 | 0.47 |
| 2010 | 0.92 | 1.31 | 0.69 |
| 2009 | 1.37 | 1.66 | 1.19 |
| 2008 | 1.95 | 3.9 | 1.06 |
| 2007 | 3.18 | 4.74 | 1.89 |
| 2006 | 1.59 | 2 | 1.26 |
| 2005 | 1.67 | 2.23 | 1.27 |
| 2004 | 2.57 | 4.58 | 1.45 |