| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.31 | 1.36 | 1.22 |
| 2024 | 1.4 | 1.65 | 1.08 |
| 2023 | 1.98 | 2.86 | 1.43 |
| 2022 | 1.86 | 2.71 | 1.38 |
| 2021 | 1.79 | 3.1 | 1.1 |
| 2020 | 1.58 | 1.99 | 1.32 |
| 2019 | 1.65 | 1.98 | 1.25 |
| 2018 | 1.72 | 2.15 | 1.33 |
| 2017 | 2.41 | 3.14 | 1.96 |
| 2016 | 3.08 | 4.37 | 2.73 |
| 2015 | 5.57 | 8.61 | 3.4 |
| 2014 | 6.26 | 9.53 | 4.76 |
| 2013 | 5.32 | 7.99 | 3.37 |
| 2012 | 4.43 | 6.16 | 3.07 |
| 2011 | 5.68 | 6.91 | 4.56 |
| 2010 | 3.94 | 6 | 2.79 |
| 2009 | 2.9 | 3.88 | 1.93 |
| 2008 | 2.3 | 4.36 | 1.22 |
| 2007 | 3.6 | 6.38 | 2.16 |
| 2006 | 1.69 | 2.22 | 1.37 |
| 2005 | 1.56 | 2.26 | 1.15 |
| 2004 | 2.42 | 3.43 | 1.74 |
| 2003 | 3.31 | 4.21 | 2.32 |