| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2024 | 1.71 | 2.14 | 1.31 |
| 2023 | 1.17 | 1.6 | 0.89 |
| 2022 | 1.4 | 1.96 | 1.06 |
| 2021 | 1.1 | 2.01 | 0.68 |
| 2020 | 0.67 | 1.06 | 0.47 |
| 2019 | 0.69 | 0.96 | 0.56 |
| 2018 | 0.91 | 1.25 | 0.71 |
| 2017 | 1.31 | 1.86 | 0.94 |
| 2016 | 1.51 | 2.25 | 1.02 |
| 2015 | 1.48 | 2.38 | 1.02 |
| 2014 | 2.24 | 3.43 | 1.04 |
| 2013 | 0.81 | 2.21 | 0.41 |
| 2012 | 1.13 | 1.97 | 0.4 |
| 2011 | 2.68 | 3.58 | 1.63 |
| 2010 | 3.29 | 4.68 | 2.18 |
| 2009 | 3.26 | 5.14 | 1.19 |
| 2008 | 3.83 | 6.83 | 1.07 |
| 2007 | 5.84 | 8.01 | 4.36 |