| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.3 | 0.33 | 0.29 |
| 2024 | 0.24 | 0.35 | 0.19 |
| 2023 | 0.23 | 0.25 | 0.21 |
| 2022 | 0.25 | 0.31 | 0.21 |
| 2021 | 0.31 | 0.41 | 0.26 |
| 2020 | 0.31 | 0.44 | 0.25 |
| 2019 | 0.34 | 0.39 | 0.3 |
| 2018 | 0.41 | 0.52 | 0.3 |
| 2017 | 0.44 | 0.5 | 0.36 |
| 2016 | 0.35 | 0.39 | 0.31 |
| 2015 | 0.39 | 0.49 | 0.25 |
| 2014 | 0.3 | 0.41 | 0.25 |
| 2013 | 0.32 | 0.41 | 0.26 |
| 2012 | 0.36 | 0.49 | 0.26 |
| 2011 | 0.47 | 0.63 | 0.32 |
| 2010 | 0.79 | 1.43 | 0.49 |
| 2009 | 0.95 | 1.43 | 0.33 |
| 2008 | 0.71 | 1.84 | 0.29 |
| 2007 | 3.79 | 11.08 | 1.4 |
| 2006 | 2.34 | 6.62 | 1.64 |
| 2005 | 2.03 | 2.77 | 1.2 |
| 2004 | 3.03 | 5.9 | 1.23 |