| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.87 | 2.59 | 1.49 |
| 2024 | 1.65 | 2.36 | 1.21 |
| 2023 | 2.56 | 3.44 | 2.15 |
| 2022 | 2.64 | 3.79 | 2.14 |
| 2021 | 2.33 | 2.94 | 1.93 |
| 2020 | 2.81 | 3.56 | 2.22 |
| 2019 | 4.08 | 5.56 | 2.76 |
| 2018 | 4.55 | 4.99 | 4.13 |
| 2017 | 5.79 | 7.19 | 4.74 |
| 2016 | 6.83 | 7.99 | 5.65 |
| 2015 | 8.19 | 12.1 | 5 |
| 2014 | 4.53 | 7.08 | 2.92 |
| 2013 | 3.42 | 5.51 | 2.59 |
| 2012 | 3.32 | 3.88 | 2.81 |
| 2011 | 3.93 | 4.78 | 3.18 |
| 2010 | 3.74 | 4.5 | 2.83 |
| 2009 | 3.3 | 4.21 | 2.65 |
| 2008 | 3.99 | 6.35 | 1.93 |
| 2007 | 4.08 | 6.6 | 1.82 |
| 2006 | 1.83 | 2.5 | 1.35 |
| 2005 | 1.53 | 2.13 | 1.07 |