| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.64 | 0.73 | 0.56 |
| 2024 | 0.52 | 0.81 | 0.29 |
| 2023 | 0.55 | 0.71 | 0.43 |
| 2022 | 0.55 | 0.76 | 0.43 |
| 2021 | 0.83 | 1.12 | 0.57 |
| 2020 | 0.88 | 1.26 | 0.64 |
| 2019 | 1.17 | 2.1 | 0.9 |
| 2018 | 5.12 | 12.53 | 1.22 |
| 2017 | 7.14 | 10.43 | 5.34 |
| 2016 | 7.97 | 9.9 | 5.93 |
| 2015 | 7.11 | 14.9 | 1.5 |
| 2014 | 0.88 | 1.82 | 0.47 |
| 2013 | 0.64 | 1.07 | 0.47 |
| 2012 | 0.81 | 1 | 0.63 |
| 2011 | 0.94 | 1.12 | 0.72 |
| 2010 | 1.1 | 1.51 | 0.79 |
| 2009 | 1.09 | 1.67 | 0.5 |
| 2008 | 1.11 | 2.21 | 0.39 |
| 2007 | 1.73 | 2.53 | 1.08 |
| 2006 | 0.71 | 1.23 | 0.45 |
| 2005 | 0.45 | 0.61 | 0.32 |
| 2004 | 0.61 | 1.3 | 0.38 |