| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.91 | 0.95 | 0.86 |
| 2024 | 0.89 | 1.04 | 0.75 |
| 2023 | 0.96 | 1.11 | 0.83 |
| 2022 | 1.11 | 1.42 | 0.94 |
| 2021 | 1.59 | 2.25 | 1.33 |
| 2020 | 1.75 | 2.11 | 1.57 |
| 2019 | 2.19 | 4.12 | 1.49 |
| 2018 | 2.02 | 2.62 | 1.43 |
| 2017 | 2.07 | 2.41 | 1.85 |
| 2016 | 2.16 | 2.64 | 1.8 |
| 2015 | 3.4 | 5.29 | 2.38 |
| 2014 | 2.36 | 3.09 | 1.98 |
| 2013 | 2 | 2.5 | 1.21 |
| 2012 | 1.27 | 1.63 | 1.05 |
| 2011 | 2.2 | 3.16 | 1.22 |
| 2010 | 3.41 | 4.55 | 2.61 |
| 2009 | 3.07 | 4.12 | 1.41 |
| 2008 | 3.88 | 8.85 | 1.03 |
| 2007 | 5.66 | 8.79 | 2.31 |
| 2006 | 2.18 | 2.55 | 1.89 |
| 2005 | 2.97 | 4.15 | 1.85 |
| 2004 | 3.99 | 4.98 | 1.93 |