| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.8 | 0.89 | 0.71 |
| 2024 | 0.73 | 0.89 | 0.61 |
| 2023 | 0.9 | 1.13 | 0.79 |
| 2022 | 0.93 | 1.09 | 0.79 |
| 2021 | 0.95 | 1.26 | 0.81 |
| 2020 | 1.19 | 1.69 | 0.86 |
| 2019 | 1.05 | 1.45 | 0.88 |
| 2018 | 1.17 | 1.5 | 0.89 |
| 2017 | 1.62 | 1.79 | 1.38 |
| 2016 | 2.1 | 3.37 | 1.69 |
| 2015 | 4.36 | 9.67 | 2.41 |
| 2014 | 2.07 | 3.04 | 1.3 |
| 2013 | 1.41 | 1.98 | 1.16 |
| 2012 | 1.49 | 1.9 | 1.13 |
| 2011 | 2.24 | 2.9 | 1.59 |
| 2010 | 3.46 | 4.55 | 2.68 |
| 2009 | 2.88 | 3.62 | 2.3 |
| 2008 | 4.29 | 9.2 | 1.95 |
| 2007 | 7.35 | 10.41 | 3.62 |
| 2006 | 3.38 | 5.08 | 2.45 |
| 2005 | 3.3 | 4.07 | 2.24 |
| 2004 | 3.72 | 4.71 | 2.98 |
| 2003 | 3.82 | 4.59 | 2.87 |
| 2002 | 4.45 | 4.82 | 4.24 |