| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.72 | 0.83 | 0.5 |
| 2024 | 0.74 | 1 | 0.58 |
| 2023 | 0.95 | 1.21 | 0.77 |
| 2022 | 1.05 | 1.28 | 0.75 |
| 2021 | 1.23 | 1.51 | 1.05 |
| 2020 | 1.27 | 1.68 | 0.95 |
| 2019 | 1.15 | 1.44 | 0.72 |
| 2018 | 2.04 | 3.39 | 0.77 |
| 2017 | 3.39 | 4.2 | 2.73 |
| 2016 | 3.84 | 4.87 | 3.31 |
| 2015 | 5.48 | 8.34 | 2.99 |
| 2014 | 3.33 | 4.02 | 2.55 |
| 2013 | 2.42 | 3.13 | 1.93 |
| 2012 | 2.92 | 4.07 | 1.96 |
| 2011 | 4.86 | 7.72 | 3.27 |
| 2010 | 6.93 | 8.63 | 5.53 |
| 2009 | 4.46 | 6.76 | 2.81 |
| 2008 | 4.46 | 10.17 | 1.59 |
| 2007 | 9.83 | 13.77 | 6.94 |
| 2006 | 4.39 | 7.01 | 2.72 |
| 2005 | 3.11 | 4.01 | 2.31 |
| 2004 | 4.2 | 7.01 | 2.57 |