| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2026 | 1.77 | 1.99 | 1.53 |
| 2025 | 1.32 | 1.8 | 1.05 |
| 2024 | 1.02 | 1.26 | 0.74 |
| 2023 | 1.27 | 1.81 | 0.94 |
| 2022 | 1.53 | 2.36 | 1.16 |
| 2021 | 1.38 | 2.3 | 1 |
| 2020 | 1.16 | 1.45 | 0.97 |
| 2019 | 1.01 | 1.24 | 0.8 |
| 2018 | 1.15 | 1.71 | 0.79 |
| 2017 | 2.12 | 2.49 | 1.63 |
| 2016 | 2.19 | 2.77 | 1.76 |
| 2015 | 2.71 | 5.69 | 1.47 |
| 2014 | 1.16 | 1.81 | 0.83 |
| 2013 | 1.18 | 1.59 | 0.92 |
| 2012 | 1.39 | 1.57 | 1.13 |
| 2011 | 2.03 | 2.88 | 1.18 |
| 2010 | 2.07 | 3.29 | 1.48 |
| 2009 | 1.82 | 2.9 | 0.82 |
| 2008 | 1.7 | 3.6 | 0.66 |
| 2007 | 2.55 | 3.98 | 0.93 |
| 2006 | 0.7 | 0.93 | 0.53 |
| 2005 | 0.6 | 0.73 | 0.41 |
| 2004 | 0.82 | 1.44 | 0.46 |