| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.26 | 1.39 | 1.2 |
| 2024 | 1.2 | 1.46 | 0.94 |
| 2023 | 1.13 | 1.48 | 0.96 |
| 2022 | 1.13 | 1.43 | 0.94 |
| 2021 | 1.94 | 3.41 | 1.17 |
| 2020 | 2.93 | 4.07 | 1.91 |
| 2019 | 2.22 | 2.96 | 1.48 |
| 2018 | 1.48 | 1.91 | 0.99 |
| 2017 | 3.02 | 5.7 | 1.54 |
| 2016 | 2.24 | 3.44 | 1.57 |
| 2015 | 1.84 | 2.67 | 1.1 |
| 2014 | 0.77 | 1.31 | 0.57 |
| 2013 | 0.76 | 0.99 | 0.59 |
| 2012 | 0.81 | 1 | 0.64 |
| 2011 | 1.13 | 1.79 | 0.6 |
| 2010 | 1.2 | 1.83 | 0.81 |
| 2009 | 2.68 | 4.59 | 1.29 |
| 2008 | 3.38 | 6.61 | 1.07 |
| 2007 | 8.81 | 17.84 | 4.66 |
| 2006 | 4.96 | 7.16 | 3.32 |
| 2005 | 2.51 | 4.18 | 1.33 |
| 2004 | 2.56 | 7.35 | 1.23 |