| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.4 | 1.49 | 1.34 |
| 2024 | 1.36 | 1.61 | 1.1 |
| 2023 | 1.74 | 2.31 | 1.27 |
| 2022 | 1.39 | 1.78 | 1.18 |
| 2021 | 1.61 | 1.99 | 1.21 |
| 2020 | 1.91 | 2.87 | 1.51 |
| 2019 | 2.1 | 3.13 | 1.5 |
| 2018 | 2.15 | 2.88 | 1.55 |
| 2017 | 3.37 | 6.23 | 2.29 |
| 2016 | 3.58 | 4.62 | 2.68 |
| 2015 | 3.93 | 6.14 | 2.61 |
| 2014 | 2.81 | 3.58 | 2.03 |
| 2013 | 2.55 | 3.17 | 2.06 |
| 2012 | 2.96 | 4.14 | 2.15 |
| 2011 | 5.03 | 7.16 | 2.52 |
| 2010 | 6.32 | 7.65 | 4.27 |
| 2009 | 4.45 | 6.84 | 3.07 |
| 2008 | 4.23 | 6.93 | 1.56 |
| 2007 | 3.35 | 5.57 | 1.88 |
| 2006 | 2.46 | 3.35 | 1.54 |
| 2005 | 2.52 | 3.38 | 1.89 |
| 2004 | 3.46 | 5.86 | 2.06 |