| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.56 | 0.6 | 0.54 |
| 2024 | 0.61 | 0.72 | 0.48 |
| 2023 | 0.7 | 0.87 | 0.6 |
| 2022 | 0.84 | 1.24 | 0.61 |
| 2021 | 0.66 | 0.72 | 0.57 |
| 2020 | 0.8 | 1.03 | 0.63 |
| 2019 | 0.84 | 1.11 | 0.72 |
| 2018 | 1.01 | 1.52 | 0.71 |
| 2017 | 2.29 | 3.3 | 1.4 |
| 2016 | 2.89 | 3.6 | 2.3 |
| 2015 | 3.72 | 6.06 | 2.26 |
| 2014 | 2.59 | 3.81 | 2.2 |
| 2013 | 2.85 | 3.47 | 2.24 |
| 2012 | 3.6 | 5 | 2.55 |
| 2011 | 5.01 | 6.81 | 3.89 |
| 2010 | 3.89 | 5.56 | 2.8 |
| 2009 | 3.4 | 5.88 | 1.55 |
| 2008 | 2.14 | 3.52 | 1.1 |
| 2007 | 2.75 | 4.05 | 1.32 |
| 2006 | 1.4 | 2.12 | 1.11 |
| 2005 | 1.24 | 1.6 | 0.96 |
| 2004 | 1.9 | 2.6 | 1.53 |