| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2024 | 1.01 | 1.31 | 0.79 |
| 2023 | 1.07 | 1.36 | 0.88 |
| 2022 | 0.92 | 1.37 | 0.73 |
| 2021 | 1.12 | 1.79 | 0.76 |
| 2020 | 0.68 | 1.15 | 0.49 |
| 2019 | 0.56 | 0.74 | 0.43 |
| 2018 | 0.75 | 1.38 | 0.45 |
| 2017 | 1.36 | 2.27 | 0.95 |
| 2016 | 0.87 | 1.46 | 0.59 |
| 2015 | 0.67 | 1.16 | 0.43 |
| 2014 | 0.38 | 0.5 | 0.3 |
| 2013 | 0.64 | 1.05 | 0.38 |
| 2012 | 1.06 | 1.37 | 0.79 |
| 2011 | 1.72 | 2.57 | 0.88 |
| 2010 | 2.29 | 3.61 | 1.51 |
| 2009 | 2.1 | 3.84 | 0.77 |
| 2008 | 1.58 | 3.5 | 0.62 |
| 2007 | 2.29 | 4.43 | 0.9 |
| 2006 | 0.7 | 1.02 | 0.45 |
| 2005 | 0.62 | 1.06 | 0.37 |
| 2004 | 1.47 | 2.65 | 0.8 |