| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.26 | 0.27 | 0.23 |
| 2024 | 0.26 | 0.33 | 0.2 |
| 2023 | 0.28 | 0.32 | 0.25 |
| 2022 | 0.27 | 0.33 | 0.23 |
| 2021 | 0.33 | 0.43 | 0.25 |
| 2020 | 0.49 | 1.06 | 0.28 |
| 2019 | 0.3 | 0.41 | 0.25 |
| 2018 | 0.29 | 0.4 | 0.2 |
| 2017 | 0.51 | 0.7 | 0.36 |
| 2016 | 0.75 | 1.39 | 0.57 |
| 2015 | 1.85 | 3.64 | 1.06 |
| 2014 | 0.88 | 1.34 | 0.64 |
| 2013 | 0.93 | 1.15 | 0.75 |
| 2012 | 1.14 | 1.47 | 0.81 |
| 2011 | 1.57 | 1.77 | 1.21 |
| 2010 | 2.44 | 4.62 | 1.54 |
| 2009 | 3.63 | 4.59 | 2.67 |
| 2008 | 7.25 | 19.14 | 1.79 |
| 2007 | 15.86 | 25.13 | 4.87 |
| 2006 | 5.36 | 8.1 | 3.24 |
| 2005 | 6.19 | 8.33 | 4.37 |
| 2004 | 8.93 | 15.29 | 5.73 |