| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2023 | 4.53 | 5.08 | 4.32 |
| 2022 | 4.61 | 5.12 | 4.1 |
| 2021 | 5.71 | 6.9 | 4.81 |
| 2020 | 6.04 | 6.92 | 5.57 |
| 2019 | 6.67 | 7.2 | 6.23 |
| 2018 | 7.18 | 9.74 | 6.21 |
| 2017 | 6.79 | 8.04 | 5.68 |
| 2016 | 5.58 | 5.93 | 5.11 |
| 2015 | 6.21 | 7.45 | 5.01 |
| 2014 | 4.71 | 6.17 | 4.39 |
| 2013 | 5.73 | 6.79 | 4.82 |
| 2012 | 6.61 | 7.72 | 5.73 |
| 2011 | 8.51 | 10.12 | 7.09 |
| 2010 | 11.24 | 15.29 | 9 |
| 2009 | 13.69 | 16.46 | 10.5 |
| 2008 | 19.84 | 37.44 | 10.68 |
| 2007 | 37.47 | 48.68 | 33.03 |