| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.88 | 0.94 | 0.83 |
| 2024 | 0.83 | 0.92 | 0.74 |
| 2023 | 0.79 | 0.86 | 0.73 |
| 2022 | 0.74 | 0.85 | 0.69 |
| 2021 | 0.74 | 0.82 | 0.68 |
| 2020 | 0.8 | 0.91 | 0.76 |
| 2019 | 0.95 | 1.11 | 0.86 |
| 2018 | 1.01 | 1.22 | 0.84 |
| 2017 | 1.22 | 1.38 | 1.13 |
| 2016 | 1.14 | 1.41 | 1.04 |
| 2015 | 1.64 | 2.69 | 1.21 |
| 2014 | 0.9 | 1.5 | 0.75 |
| 2013 | 0.8 | 0.91 | 0.69 |
| 2012 | 0.9 | 1.04 | 0.78 |
| 2011 | 1.26 | 1.53 | 0.92 |
| 2010 | 1.96 | 3.46 | 1.37 |
| 2009 | 2.29 | 2.83 | 1.92 |
| 2008 | 3.01 | 4.83 | 1.89 |
| 2007 | 3.52 | 4.5 | 2.39 |
| 2006 | 2.1 | 2.6 | 1.3 |
| 2005 | 2.5 | 2.85 | 2.11 |
| 2004 | 2.45 | 4.22 | 1.75 |
| 2003 | 4.8 | 6.27 | 3.46 |
| 2002 | 5.78 | 6.3 | 5.22 |