| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.99 | 1.19 | 0.82 |
| 2024 | 0.86 | 1.09 | 0.72 |
| 2023 | 1.05 | 1.34 | 0.86 |
| 2022 | 1 | 1.25 | 0.87 |
| 2021 | 1.19 | 1.52 | 0.94 |
| 2020 | 1.39 | 1.72 | 1.15 |
| 2019 | 1.35 | 1.89 | 1.08 |
| 2018 | 1.37 | 1.59 | 1.08 |
| 2017 | 2.19 | 2.7 | 1.59 |
| 2016 | 2.98 | 4.65 | 2.63 |
| 2015 | 16.76 | 36.9 | 3.61 |
| 2014 | 19.58 | 30.31 | 13.85 |
| 2013 | 25.03 | 39.07 | 15.99 |
| 2012 | 13.5 | 16.42 | 10.83 |
| 2011 | 0 | ||
| 2010 | 0 | ||
| 2009 | 0 | ||
| 2008 | 0 | ||
| 2007 | 0 | ||
| 2006 | 1.11 | 1.31 | 0.87 |
| 2005 | 1.13 | 1.71 | 0.78 |
| 2004 | 1.47 | 2.31 | 0.71 |
| 2003 | 2.24 | 2.75 | 1.59 |
| 2002 | 2.99 | 3.43 | 2.36 |
| 2001 | 4.25 | 5.36 | 3.06 |