| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2024 | 0.94 | 1.06 | 0.79 |
| 2023 | 0.85 | 1.03 | 0.67 |
| 2022 | 0.66 | 0.72 | 0.61 |
| 2021 | 0.69 | 0.78 | 0.63 |
| 2020 | 0.72 | 0.89 | 0.65 |
| 2019 | 0.89 | 1.03 | 0.81 |
| 2018 | 1.09 | 1.29 | 0.85 |
| 2017 | 1.01 | 1.06 | 0.94 |
| 2016 | 0.86 | 0.99 | 0.77 |
| 2015 | 1.15 | 1.77 | 0.81 |
| 2014 | 1.04 | 1.29 | 0.92 |
| 2013 | 1.07 | 1.41 | 0.87 |
| 2012 | 1.21 | 1.46 | 1.03 |
| 2011 | 1.57 | 1.98 | 1.31 |
| 2010 | 2.13 | 3.3 | 1.71 |
| 2009 | 2.76 | 3.91 | 1.97 |
| 2008 | 3.41 | 7.22 | 1.86 |
| 2007 | 4.8 | 8.43 | 3.04 |
| 2006 | 2.38 | 3.32 | 1.95 |
| 2005 | 1.56 | 1.99 | 1.16 |
| 2004 | 2.12 | 3.06 | 1.68 |
| 2003 | 2.06 | 2.69 | 1.68 |
| 2002 | 2 | 2.36 | 1.72 |