| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.4 | 0.5 | 0.32 |
| 2024 | 0.29 | 0.61 | 0.18 |
| 2023 | 0.29 | 0.36 | 0.25 |
| 2022 | 0.36 | 0.55 | 0.25 |
| 2021 | 0.58 | 0.78 | 0.42 |
| 2020 | 0.6 | 0.71 | 0.48 |
| 2019 | 0.89 | 1.27 | 0.65 |
| 2018 | 0.79 | 1.04 | 0.63 |
| 2017 | 1.69 | 3.81 | 0.72 |
| 2016 | 21.43 | 71.23 | 3.62 |
| 2015 | 19.06 | 31.62 | 6.04 |
| 2014 | 4.4 | 6.04 | 3.26 |
| 2013 | 5.03 | 6.59 | 4.09 |
| 2012 | 3.87 | 4.33 | 3.46 |
| 2011 | 4.84 | 6.04 | 3.48 |
| 2010 | 6.65 | 9.86 | 4.69 |
| 2009 | 4.82 | 6.92 | 2.26 |
| 2008 | 6.12 | 13.6 | 1.86 |
| 2007 | 7.79 | 13.5 | 3.24 |
| 2006 | 3.05 | 4.46 | 2.19 |
| 2005 | 2.68 | 3.96 | 2.01 |
| 2004 | 3.53 | 6.04 | 2.23 |