| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.56 | 0.6 | 0.49 |
| 2024 | 0.43 | 0.66 | 0.31 |
| 2023 | 0.61 | 0.77 | 0.52 |
| 2022 | 0.77 | 0.94 | 0.59 |
| 2021 | 0.73 | 0.94 | 0.55 |
| 2020 | 1.14 | 1.4 | 0.71 |
| 2019 | 1.13 | 1.46 | 0.96 |
| 2018 | 1.77 | 2.55 | 0.98 |
| 2017 | 2.53 | 3.11 | 2.12 |
| 2016 | 2.5 | 3.5 | 1.51 |
| 2015 | 3.08 | 5.15 | 1.62 |
| 2014 | 1.14 | 2.05 | 0.96 |
| 2013 | 1.39 | 1.93 | 1.09 |
| 2012 | 1.95 | 2.59 | 1.28 |
| 2011 | 2.33 | 2.98 | 1.87 |
| 2010 | 2.55 | 3.8 | 1.59 |
| 2009 | 2.98 | 5.66 | 1.31 |
| 2008 | 2.68 | 5.48 | 1.02 |
| 2007 | 3.36 | 4.34 | 2.13 |
| 2006 | 1.76 | 2.31 | 1.26 |
| 2005 | 1.72 | 2.12 | 1.13 |