| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 2.52 | 2.8 | 2.29 |
| 2024 | 2.82 | 3.82 | 2.23 |
| 2023 | 2.53 | 3.39 | 1.53 |
| 2022 | 1.85 | 2.51 | 1.45 |
| 2021 | 2.91 | 3.79 | 2.31 |
| 2020 | 2.47 | 3.19 | 2 |
| 2019 | 3.44 | 4.79 | 2.8 |
| 2018 | 3.23 | 3.93 | 2.48 |
| 2017 | 2.88 | 3.14 | 2.71 |
| 2016 | 2.41 | 3.02 | 1.39 |
| 2015 | 2.27 | 3.46 | 1.49 |
| 2014 | 1.12 | 1.88 | 0.84 |
| 2013 | 1.36 | 1.76 | 1.05 |
| 2012 | 1.6 | 2.02 | 1.29 |
| 2011 | 1.74 | 2.39 | 1.37 |
| 2010 | 2.45 | 3.16 | 1.96 |
| 2009 | 2.54 | 3.31 | 1.57 |
| 2008 | 3.8 | 8.85 | 1.43 |
| 2007 | 7.92 | 12.7 | 2.89 |
| 2006 | 1.83 | 2.8 | 1.07 |
| 2005 | 1.26 | 1.69 | 0.89 |
| 2004 | 1.96 | 3 | 1.27 |