| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.98 | 1.1 | 0.9 |
| 2024 | 1.01 | 1.37 | 0.73 |
| 2023 | 0.87 | 1.08 | 0.73 |
| 2022 | 0.89 | 1.24 | 0.7 |
| 2021 | 1.4 | 1.99 | 1.2 |
| 2020 | 1.04 | 1.5 | 0.82 |
| 2019 | 1.02 | 1.19 | 0.91 |
| 2018 | 1.15 | 1.61 | 0.9 |
| 2017 | 1.31 | 1.59 | 1.08 |
| 2016 | 1.11 | 1.57 | 0.9 |
| 2015 | 1.38 | 2.18 | 0.9 |
| 2014 | 1.06 | 1.44 | 0.91 |
| 2013 | 1.53 | 2.27 | 1.11 |
| 2012 | 2.02 | 2.42 | 1.66 |
| 2011 | 3.28 | 4.9 | 1.86 |
| 2010 | 4.31 | 7.27 | 2.86 |
| 2009 | 4.4 | 7.09 | 1.6 |
| 2008 | 4.35 | 11.71 | 1.24 |
| 2007 | 7.01 | 17.08 | 2.87 |
| 2006 | 3 | 5.27 | 1.88 |
| 2005 | 1.3 | 1.87 | 0.92 |
| 2004 | 2.03 | 2.88 | 1.45 |
| 2003 | 1.76 | 2.61 | 1.55 |