| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 2.98 | 3.22 | 2.72 |
| 2024 | 2.72 | 3.82 | 2.13 |
| 2023 | 2.69 | 3.44 | 2.17 |
| 2022 | 2.45 | 3.13 | 1.92 |
| 2021 | 2.98 | 3.74 | 2.3 |
| 2020 | 3.05 | 3.65 | 2.29 |
| 2019 | 11.85 | 18.98 | 2.74 |
| 2018 | 10.75 | 12.72 | 8.02 |
| 2017 | 11.46 | 13.35 | 9.84 |
| 2016 | 8.71 | 12.79 | 5.82 |
| 2015 | 15.58 | 26.51 | 5.52 |
| 2014 | 13.43 | 26.6 | 10.07 |
| 2013 | 17.41 | 23.46 | 12.16 |
| 2012 | 12.78 | 18.82 | 5.93 |
| 2011 | 8.96 | 10.88 | 6.22 |
| 2010 | 11.92 | 18.96 | 8.18 |
| 2009 | 17.85 | 32.56 | 6.34 |
| 2008 | 9.33 | 19.27 | 5.26 |
| 2007 | 11.1 | 25.81 | 5.91 |
| 2006 | 18.5 | 34.3 | 8.11 |