| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2026 | 1.66 | 2.02 | 1.37 |
| 2025 | 1.2 | 1.64 | 0.89 |
| 2024 | 1.03 | 1.27 | 0.77 |
| 2023 | 1.35 | 1.94 | 1.05 |
| 2022 | 1.46 | 1.64 | 1.11 |
| 2021 | 1.5 | 2.1 | 1.19 |
| 2020 | 0.98 | 1.48 | 0.62 |
| 2019 | 0.65 | 0.89 | 0.46 |
| 2018 | 0.62 | 0.76 | 0.47 |
| 2017 | 0.78 | 1 | 0.62 |
| 2016 | 0.82 | 1.09 | 0.61 |
| 2015 | 0.96 | 1.51 | 0.6 |
| 2014 | 0.61 | 0.88 | 0.5 |
| 2013 | 0.87 | 1.28 | 0.55 |
| 2012 | 1.58 | 2.32 | 1.03 |
| 2011 | 3.02 | 4.37 | 1.41 |
| 2010 | 2.42 | 4.77 | 1.45 |
| 2009 | 1.95 | 2.99 | 0.66 |
| 2008 | 2.07 | 6.02 | 0.45 |
| 2007 | 6.53 | 10.54 | 2.78 |
| 2006 | 3.79 | 6.62 | 2.45 |
| 2005 | 3.01 | 3.87 | 2.51 |
| 2004 | 5.54 | 9.43 | 3.26 |