| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.6 | 0.73 | 0.51 |
| 2024 | 0.58 | 0.76 | 0.46 |
| 2023 | 0.66 | 0.77 | 0.59 |
| 2022 | 0.65 | 0.79 | 0.56 |
| 2021 | 0.49 | 0.78 | 0.27 |
| 2020 | 0.35 | 0.41 | 0.28 |
| 2019 | 0.39 | 0.49 | 0.27 |
| 2018 | 1.07 | 2.17 | 0.29 |
| 2017 | 6.06 | 14.52 | 1.62 |
| 2016 | 8.72 | 13.66 | 5.04 |
| 2015 | 4.22 | 6.63 | 2.77 |
| 2014 | 1.77 | 2.88 | 1.3 |
| 2013 | 2.36 | 3.8 | 1.4 |
| 2012 | 2.68 | 4.01 | 1.95 |
| 2011 | 4.77 | 8.12 | 2.58 |
| 2010 | 2.27 | 3.78 | 1.63 |
| 2009 | 1.65 | 2.32 | 1.18 |
| 2008 | 2.93 | 7.65 | 0.91 |
| 2007 | 6.33 | 8.3 | 4.92 |