| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 2.64 | 2.9 | 2.36 |
| 2024 | 2.53 | 3.36 | 2.01 |
| 2023 | 3 | 3.64 | 2.32 |
| 2022 | 2.44 | 2.89 | 1.86 |
| 2021 | 3.33 | 4.63 | 2.39 |
| 2020 | 2.87 | 4.07 | 2.13 |
| 2019 | 2.85 | 4.06 | 2.15 |
| 2018 | 2.39 | 3.96 | 1.67 |
| 2017 | 6.84 | 10.57 | 4 |
| 2016 | 6.86 | 10.48 | 4.17 |
| 2015 | 6.24 | 9.52 | 2.74 |
| 2014 | 2.62 | 3.22 | 2.09 |
| 2013 | 4.07 | 6.02 | 3.12 |
| 2012 | 4.61 | 5.71 | 3.56 |
| 2011 | 7.09 | 9.93 | 4.86 |
| 2010 | 9.96 | 14.81 | 6.86 |
| 2009 | 10.36 | 17.31 | 3.36 |
| 2008 | 9.32 | 18.73 | 2.32 |
| 2007 | 16.61 | 26.02 | 10.42 |
| 2006 | 13.14 | 20.76 | 7.25 |
| 2005 | 4.24 | 8 | 1.53 |
| 2004 | 2.45 | 3.83 | 1.66 |