| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2024 | 1.07 | 1.4 | 0.82 |
| 2023 | 0.92 | 1.15 | 0.71 |
| 2022 | 0.89 | 1.08 | 0.77 |
| 2021 | 0.83 | 1.19 | 0.64 |
| 2020 | 0.73 | 0.92 | 0.61 |
| 2019 | 0.87 | 1.13 | 0.73 |
| 2018 | 1.07 | 1.72 | 0.76 |
| 2017 | 1.47 | 2.1 | 1.06 |
| 2016 | 1.03 | 1.34 | 0.76 |
| 2015 | 1.16 | 1.72 | 0.78 |
| 2014 | 0.89 | 1.23 | 0.72 |
| 2013 | 1.33 | 1.94 | 0.94 |
| 2012 | 2.2 | 2.88 | 1.45 |
| 2011 | 3.42 | 5.77 | 1.97 |
| 2010 | 4.82 | 14.7 | 2.5 |
| 2009 | 4.5 | 14.3 | 1.68 |
| 2008 | 4.65 | 10.27 | 1.17 |
| 2007 | 5.53 | 10.9 | 2.33 |
| 2006 | 1.95 | 2.36 | 1.55 |
| 2005 | 1.78 | 1.98 | 1.57 |