| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2024 | 1.35 | 1.78 | 1 |
| 2023 | 1.15 | 1.46 | 0.87 |
| 2022 | 0.98 | 1.43 | 0.75 |
| 2021 | 1.03 | 1.82 | 0.58 |
| 2020 | 0.71 | 0.88 | 0.61 |
| 2019 | 0.91 | 1.06 | 0.78 |
| 2018 | 1.19 | 1.84 | 0.83 |
| 2017 | 1.77 | 2.81 | 1.15 |
| 2016 | 2.06 | 3.03 | 1.4 |
| 2015 | 1.58 | 2.38 | 1.1 |
| 2014 | 1.12 | 1.66 | 0.87 |
| 2013 | 1.74 | 2.76 | 1.22 |
| 2012 | 2.25 | 2.95 | 1.71 |
| 2011 | 3.08 | 3.85 | 1.9 |
| 2010 | 2.63 | 3.62 | 1.84 |
| 2009 | 2.46 | 3.72 | 0.99 |
| 2008 | 2.95 | 5.43 | 0.7 |
| 2007 | 4.57 | 6.66 | 1.83 |