| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 4.1 | 4.6 | 3.85 |
| 2024 | 4.86 | 6.76 | 3.67 |
| 2023 | 6.62 | 7.71 | 5.52 |
| 2022 | 5.76 | 6.76 | 4.96 |
| 2021 | 5.02 | 6.57 | 3.42 |
| 2020 | 4.94 | 9.7 | 3.01 |
| 2019 | 8.16 | 11.93 | 4.37 |
| 2018 | 10.54 | 19.2 | 4.07 |
| 2017 | 13.93 | 22.22 | 9.39 |
| 2016 | 12.04 | 19.24 | 7.66 |
| 2015 | 11.68 | 14.66 | 6.53 |
| 2014 | 5.63 | 9.3 | 3.81 |
| 2013 | 4.02 | 4.98 | 3.24 |
| 2012 | 6.55 | 12.37 | 3.95 |
| 2011 | 5.77 | 12.58 | 3.51 |
| 2010 | 2.53 | 5.39 | 1.08 |
| 2009 | 0.77 | 1.47 | 0.27 |
| 2008 | 0.45 | 0.85 | 0.18 |
| 2007 | 0.79 | 1.56 | 0.54 |
| 2006 | 0.46 | 0.83 | 0.27 |
| 2005 | 0.84 | 1.18 | 0.27 |
| 2004 | 1.94 | 5.03 | 1 |