| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.37 | 0.4 | 0.34 |
| 2024 | 0.38 | 0.41 | 0.32 |
| 2023 | 0.52 | 0.66 | 0.37 |
| 2022 | 0.6 | 0.71 | 0.5 |
| 2021 | 0.83 | 0.97 | 0.67 |
| 2020 | 1.05 | 1.18 | 0.85 |
| 2019 | 1.15 | 1.44 | 0.94 |
| 2018 | 1.2 | 1.42 | 0.96 |
| 2017 | 1.38 | 2.34 | 1.03 |
| 2016 | 1.87 | 2.13 | 1.48 |
| 2015 | 1.79 | 2.96 | 1.2 |
| 2014 | 1.32 | 1.65 | 1.06 |
| 2013 | 1.16 | 1.35 | 1.04 |
| 2012 | 1.1 | 1.34 | 0.84 |
| 2011 | 1.52 | 2.1 | 0.93 |
| 2010 | 1.98 | 2.28 | 1.58 |
| 2009 | 1.56 | 2.09 | 0.92 |
| 2008 | 1.73 | 3.14 | 0.65 |
| 2007 | 2.59 | 4.06 | 1.54 |
| 2006 | 1.42 | 1.79 | 0.91 |
| 2005 | 0.55 | 1.05 | 0.34 |
| 2004 | 0.86 | 1.57 | 0.46 |