| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.97 | 1.12 | 0.86 |
| 2024 | 0.78 | 1.14 | 0.47 |
| 2023 | 0.66 | 0.74 | 0.52 |
| 2022 | 0.67 | 1.08 | 0.51 |
| 2021 | 1.35 | 2.34 | 0.91 |
| 2020 | 1 | 1.4 | 0.86 |
| 2019 | 0.9 | 1.15 | 0.73 |
| 2018 | 0.99 | 1.47 | 0.68 |
| 2017 | 1.69 | 2.27 | 1.23 |
| 2016 | 1.53 | 2.2 | 1.19 |
| 2015 | 2.17 | 3.63 | 1.44 |
| 2014 | 1 | 1.63 | 0.64 |
| 2013 | 0.69 | 0.81 | 0.58 |
| 2012 | 0.72 | 0.94 | 0.57 |
| 2011 | 1.16 | 1.66 | 0.62 |
| 2010 | 1.54 | 2.24 | 1.16 |
| 2009 | 1.49 | 2.31 | 0.66 |
| 2008 | 1.36 | 3.12 | 0.51 |
| 2007 | 2.51 | 3.55 | 1.12 |
| 2006 | 0.88 | 1.29 | 0.68 |
| 2005 | 0.91 | 1.45 | 0.62 |
| 2004 | 1.99 | 3.79 | 1.07 |