| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.1 | 1.21 | 1 |
| 2024 | 1.16 | 1.46 | 0.87 |
| 2023 | 1.28 | 1.88 | 1.05 |
| 2022 | 1.1 | 1.41 | 0.98 |
| 2021 | 1.18 | 1.4 | 1.05 |
| 2020 | 1.3 | 1.52 | 1.14 |
| 2019 | 1.38 | 1.81 | 1.14 |
| 2018 | 1.85 | 2.36 | 1.41 |
| 2017 | 3.91 | 13.24 | 2.18 |
| 2016 | 6.78 | 8.55 | 5.69 |
| 2015 | 8.71 | 13.76 | 5.58 |
| 2014 | 5.39 | 6.93 | 4.33 |
| 2013 | 4.8 | 5.96 | 4.12 |
| 2012 | 4.23 | 4.99 | 3.61 |
| 2011 | 5.64 | 8.14 | 3.64 |
| 2010 | 7.38 | 9.51 | 5.7 |
| 2009 | 5.16 | 7.52 | 3.22 |
| 2008 | 4.34 | 8.05 | 2.33 |
| 2007 | 5.92 | 8.18 | 3.62 |
| 2006 | 3.68 | 4.72 | 3 |
| 2005 | 2.87 | 3.7 | 1.4 |