| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.92 | 0.95 | 0.85 |
| 2024 | 0.94 | 1.06 | 0.81 |
| 2023 | 1.21 | 1.67 | 0.92 |
| 2022 | 1.65 | 2.26 | 1.23 |
| 2021 | 2.34 | 3.29 | 1.74 |
| 2020 | 1.69 | 2.42 | 1.24 |
| 2019 | 1.3 | 1.55 | 1.01 |
| 2018 | 1.46 | 2.23 | 0.97 |
| 2017 | 2.3 | 3 | 1.88 |
| 2016 | 2.97 | 3.71 | 2.63 |
| 2015 | 3.36 | 5.25 | 2.24 |
| 2014 | 2.13 | 2.61 | 1.78 |
| 2013 | 2.59 | 3.58 | 2.09 |
| 2012 | 2.32 | 2.7 | 1.93 |
| 2011 | 4.2 | 6.66 | 2.07 |
| 2010 | 4.95 | 6.91 | 3.09 |
| 2009 | 4.55 | 6.09 | 2.46 |
| 2008 | 4.22 | 7.49 | 1.69 |
| 2007 | 5.55 | 9.04 | 3.82 |
| 2006 | 3.08 | 4.32 | 2.22 |
| 2005 | 1.42 | 2.38 | 0.94 |
| 2004 | 1.95 | 3.42 | 1.23 |