| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.11 | 1.19 | 1.06 |
| 2024 | 1.08 | 1.26 | 0.91 |
| 2023 | 1.28 | 1.49 | 1.18 |
| 2022 | 1.54 | 1.96 | 1.22 |
| 2021 | 1.7 | 2.41 | 1.45 |
| 2020 | 1.99 | 2.75 | 1.65 |
| 2019 | 2.39 | 3.72 | 1.84 |
| 2018 | 2.04 | 2.32 | 1.74 |
| 2017 | 2.96 | 3.4 | 2.29 |
| 2016 | 3.21 | 3.98 | 2.7 |
| 2015 | 5.65 | 9.61 | 3.36 |
| 2014 | 6.03 | 22.61 | 3.33 |
| 2013 | 3.15 | 4.38 | 2.53 |
| 2012 | 3.42 | 4.4 | 2.53 |
| 2011 | 4.11 | 5.77 | 2.76 |
| 2010 | 5.64 | 7.4 | 4.48 |
| 2009 | 2.38 | 5.86 | 1.05 |
| 2008 | 1.9 | 3.83 | 0.81 |
| 2007 | 3.03 | 5.31 | 0.98 |
| 2006 | 0.94 | 1.08 | 0.79 |
| 2005 | 1.03 | 1.35 | 0.74 |
| 2004 | 1.67 | 2.15 | 1.33 |