| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.56 | 1.79 | 1.38 |
| 2024 | 1.21 | 1.81 | 0.91 |
| 2023 | 1.05 | 1.35 | 0.61 |
| 2022 | 0.62 | 0.98 | 0.4 |
| 2021 | 0.71 | 0.84 | 0.52 |
| 2020 | 0.99 | 1.34 | 0.79 |
| 2019 | 1.26 | 1.67 | 1.01 |
| 2018 | 1.49 | 1.92 | 1.12 |
| 2017 | 1.53 | 1.82 | 1.35 |
| 2016 | 2.58 | 3.71 | 1.61 |
| 2015 | 3.63 | 5.71 | 2.39 |
| 2014 | 2.1 | 2.93 | 1.64 |
| 2013 | 2 | 3.59 | 1.26 |
| 2012 | 2.48 | 3.72 | 1.53 |
| 2011 | 4.35 | 5.91 | 2.69 |
| 2010 | 6.25 | 9.03 | 4.54 |
| 2009 | 7.18 | 9.1 | 5.35 |
| 2008 | 13.46 | 25.29 | 4.64 |
| 2007 | 20.8 | 28.78 | 12.11 |
| 2006 | 9.82 | 15.87 | 5.95 |
| 2005 | 6.59 | 7.74 | 5.38 |