| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.97 | 1.05 | 0.92 |
| 2024 | 0.97 | 1.2 | 0.6 |
| 2023 | 1.05 | 1.37 | 0.94 |
| 2022 | 0.96 | 1.22 | 0.69 |
| 2021 | 0.76 | 0.85 | 0.69 |
| 2020 | 0.91 | 1.21 | 0.78 |
| 2019 | 0.99 | 1.22 | 0.85 |
| 2018 | 1.01 | 1.27 | 0.71 |
| 2017 | 1.7 | 2.4 | 1.14 |
| 2016 | 2.29 | 2.68 | 1.91 |
| 2015 | 2.81 | 4.16 | 1.87 |
| 2014 | 2.6 | 3.85 | 2.09 |
| 2013 | 1.87 | 3.01 | 1.43 |
| 2012 | 1.85 | 2.35 | 1.38 |
| 2011 | 2.3 | 2.77 | 1.91 |
| 2010 | 3.52 | 4.55 | 2.59 |
| 2009 | 10.19 | 40.04 | 2.7 |
| 2008 | 12.88 | 23.94 | 7.95 |
| 2007 | 6.68 | 9.75 | 3.51 |
| 2006 | 3.68 | 5.11 | 3.15 |
| 2005 | 3.79 | 5.15 | 2.69 |
| 2004 | 5.57 | 7.6 | 4.31 |
| 2003 | 7.37 | 10.71 | 4.14 |