| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.81 | 0.87 | 0.76 |
| 2024 | 0.78 | 0.96 | 0.61 |
| 2023 | 0.86 | 1.19 | 0.67 |
| 2022 | 1.19 | 1.54 | 0.85 |
| 2021 | 1.09 | 2.43 | 0.44 |
| 2020 | 0.95 | 2 | 0.47 |
| 2019 | 0.93 | 1.14 | 0.82 |
| 2018 | 1.16 | 1.72 | 0.82 |
| 2017 | 1.95 | 2.47 | 1.64 |
| 2016 | 2.35 | 3.1 | 1.73 |
| 2015 | 1.89 | 3.07 | 1.2 |
| 2014 | 1.33 | 1.61 | 1.14 |
| 2013 | 1.46 | 1.73 | 1.23 |
| 2012 | 1.86 | 2.61 | 1.19 |
| 2011 | 2.91 | 4.57 | 1.74 |
| 2010 | 3.26 | 4.44 | 2.02 |
| 2009 | 3.48 | 4.6 | 1.93 |
| 2008 | 3.9 | 7.77 | 1.51 |
| 2007 | 5.09 | 7.6 | 2.01 |
| 2006 | 2.46 | 3.57 | 1.82 |
| 2005 | 2.48 | 3.64 | 1.52 |
| 2004 | 3.47 | 6.28 | 1.55 |