| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2024 | 0.41 | 0.47 | 0.36 |
| 2023 | 0.4 | 0.52 | 0.33 |
| 2022 | 0.43 | 0.53 | 0.35 |
| 2021 | 0.53 | 0.8 | 0.4 |
| 2020 | 0.89 | 1.35 | 0.31 |
| 2019 | 0.96 | 1.18 | 0.77 |
| 2018 | 1.36 | 1.7 | 0.95 |
| 2017 | 2 | 2.73 | 1.42 |
| 2016 | 2.14 | 2.69 | 1.79 |
| 2015 | 3.22 | 5.57 | 1.94 |
| 2014 | 2.55 | 3.37 | 2.01 |
| 2013 | 2.57 | 4.98 | 1.36 |
| 2012 | 1.77 | 2.37 | 1.18 |
| 2011 | 4.23 | 7.58 | 2.14 |
| 2010 | 4.49 | 5.61 | 3.38 |
| 2009 | 2.84 | 4.24 | 1.84 |
| 2008 | 2.95 | 5.73 | 1.31 |
| 2007 | 2.63 | 4.34 | 1.5 |
| 2006 | 1.49 | 1.93 | 0.77 |
| 2005 | 1.17 | 1.77 | 0.87 |
| 2004 | 1.81 | 2.97 | 1.1 |