| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.16 | 1.43 | 0.96 |
| 2024 | 0.97 | 1.36 | 0.77 |
| 2023 | 0.99 | 1.17 | 0.87 |
| 2022 | 0.86 | 1.16 | 0.62 |
| 2021 | 0.63 | 0.86 | 0.42 |
| 2020 | 0.68 | 0.84 | 0.61 |
| 2019 | 0.78 | 0.96 | 0.64 |
| 2018 | 0.97 | 1.25 | 0.61 |
| 2017 | 1.65 | 3.06 | 1.16 |
| 2016 | 2.05 | 3.44 | 1.26 |
| 2015 | 2.09 | 3.34 | 1.24 |
| 2014 | 1.77 | 2.83 | 1.49 |
| 2013 | 1.6 | 2.07 | 1.36 |
| 2012 | 1.98 | 2.48 | 1.44 |
| 2011 | 3.07 | 4.39 | 1.82 |
| 2010 | 3.4 | 4.25 | 2.39 |
| 2009 | 2.98 | 4.23 | 1.69 |
| 2008 | 4.05 | 8.63 | 1.48 |
| 2007 | 4.62 | 7.64 | 2.58 |
| 2006 | 1.88 | 2.71 | 1.17 |
| 2005 | 1.27 | 1.64 | 0.9 |
| 2004 | 1.97 | 2.68 | 1.6 |
| 2003 | 2.6 | 3.18 | 1.96 |
| 2002 | 3.94 | 4.29 | 3.53 |