| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.67 | 0.72 | 0.62 |
| 2024 | 0.76 | 0.9 | 0.6 |
| 2023 | 0.81 | 0.91 | 0.74 |
| 2022 | 0.94 | 1.43 | 0.62 |
| 2021 | 0.7 | 0.98 | 0.57 |
| 2020 | 0.63 | 0.76 | 0.56 |
| 2019 | 0.73 | 0.85 | 0.64 |
| 2018 | 0.86 | 1.08 | 0.72 |
| 2017 | 1 | 1.17 | 0.87 |
| 2016 | 0.88 | 1.02 | 0.77 |
| 2015 | 1.05 | 1.63 | 0.79 |
| 2014 | 0.8 | 1.04 | 0.69 |
| 2013 | 1.12 | 1.6 | 0.83 |
| 2012 | 1.79 | 2.33 | 1.22 |
| 2011 | 2.79 | 3.85 | 1.85 |
| 2010 | 3.3 | 4.76 | 2.27 |
| 2009 | 3.23 | 4.68 | 1.8 |
| 2008 | 4.27 | 9.73 | 1.58 |
| 2007 | 5.63 | 11.39 | 2.29 |
| 2006 | 2.12 | 2.89 | 1.65 |
| 2005 | 2.14 | 2.91 | 1.64 |
| 2004 | 2.89 | 3.44 | 2.39 |
| 2003 | 2.88 | 3.3 | 2.49 |
| 2002 | 3.3 | 3.88 | 2.64 |