| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 2.7 | 3.04 | 2.52 |
| 2024 | 2.54 | 2.86 | 2.06 |
| 2023 | 2.43 | 2.65 | 2.07 |
| 2022 | 2.23 | 2.62 | 1.88 |
| 2021 | 2.42 | 2.86 | 1.98 |
| 2020 | 2.85 | 3.61 | 2.33 |
| 2019 | 2.17 | 2.76 | 1.84 |
| 2018 | 1.95 | 2.5 | 1.55 |
| 2017 | 2.73 | 3.32 | 2.28 |
| 2016 | 3.4 | 3.94 | 2.89 |
| 2015 | 3.18 | 6.66 | 1.87 |
| 2014 | 1.84 | 2.11 | 1.62 |
| 2013 | 2.12 | 2.57 | 1.71 |
| 2012 | 3.14 | 4.29 | 1.96 |
| 2011 | 3.91 | 5.32 | 3.05 |
| 2010 | 3.93 | 4.74 | 3.29 |
| 2009 | 2.78 | 4.12 | 1.83 |
| 2008 | 2.28 | 4.07 | 1.19 |
| 2007 | 4.45 | 8.99 | 2.37 |
| 2006 | 2.11 | 2.52 | 1.67 |
| 2005 | 2.09 | 2.79 | 1.65 |