| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.6 | 1.8 | 1.38 |
| 2024 | 1.2 | 1.77 | 0.85 |
| 2023 | 1.3 | 1.43 | 1.16 |
| 2022 | 1.32 | 1.8 | 0.95 |
| 2021 | 1.61 | 2.22 | 1.23 |
| 2020 | 1.47 | 1.88 | 1.15 |
| 2019 | 1.42 | 1.95 | 0.93 |
| 2018 | 1.39 | 2.03 | 0.84 |
| 2017 | 2.5 | 3.07 | 1.95 |
| 2016 | 3.25 | 4.4 | 1.9 |
| 2015 | 2.59 | 4.32 | 1.87 |
| 2014 | 1.93 | 2.27 | 1.48 |
| 2013 | 2 | 2.62 | 1.62 |
| 2012 | 2.66 | 3.83 | 1.72 |
| 2011 | 4.78 | 5.97 | 3.4 |
| 2010 | 4.7 | 7.42 | 3.46 |
| 2009 | 3.5 | 4.81 | 1.65 |
| 2008 | 2.53 | 4.55 | 0.86 |
| 2007 | 3.05 | 4.18 | 2.32 |
| 2006 | 1.6 | 2.36 | 1.06 |
| 2005 | 1.48 | 2.04 | 1.03 |
| 2004 | 2.35 | 4.38 | 1.46 |