| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.78 | 0.92 | 0.73 |
| 2024 | 0.85 | 1 | 0.72 |
| 2023 | 1.03 | 1.49 | 0.79 |
| 2022 | 1.02 | 1.3 | 0.85 |
| 2021 | 1.09 | 1.29 | 0.97 |
| 2020 | 1.49 | 2.84 | 1.01 |
| 2019 | 2.26 | 2.81 | 1.96 |
| 2018 | 2.57 | 3.13 | 2.14 |
| 2017 | 2.48 | 2.88 | 2.23 |
| 2016 | 2.07 | 2.46 | 1.57 |
| 2015 | 2.46 | 3.56 | 1.76 |
| 2014 | 1.7 | 2.21 | 1.47 |
| 2013 | 2.1 | 2.45 | 1.82 |
| 2012 | 2.79 | 3.67 | 1.8 |
| 2011 | 3.72 | 4.69 | 3.04 |
| 2010 | 2.43 | 3.64 | 1.4 |
| 2009 | 3.54 | 4.85 | 2.65 |
| 2008 | 6.08 | 9.29 | 2.7 |
| 2007 | 7.02 | 9.53 | 5.31 |
| 2006 | 3.73 | 6.02 | 2.17 |
| 2005 | 2.27 | 2.76 | 1.49 |
| 2004 | 1.9 | 2.69 | 1.46 |