| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.97 | 1.4 | 0.78 |
| 2024 | 0.72 | 0.92 | 0.55 |
| 2023 | 0.86 | 1.01 | 0.71 |
| 2022 | 1.01 | 1.25 | 0.74 |
| 2021 | 1.02 | 1.42 | 0.8 |
| 2020 | 1.08 | 1.76 | 0.61 |
| 2019 | 0.78 | 1.17 | 0.55 |
| 2018 | 0.53 | 0.73 | 0.44 |
| 2017 | 0.73 | 1 | 0.56 |
| 2016 | 0.9 | 1.26 | 0.78 |
| 2015 | 1.32 | 2.34 | 0.86 |
| 2014 | 0.75 | 0.97 | 0.59 |
| 2013 | 0.87 | 1.12 | 0.66 |
| 2012 | 1.47 | 2.31 | 0.76 |
| 2011 | 3.22 | 4.61 | 1.63 |
| 2010 | 3.01 | 4.54 | 2.02 |
| 2009 | 1.76 | 2.24 | 1.44 |
| 2008 | 2.18 | 3.86 | 0.85 |
| 2007 | 2.66 | 3.51 | 1.71 |
| 2006 | 1.78 | 2.18 | 1.2 |
| 2005 | 1.23 | 1.63 | 0.88 |
| 2004 | 1.82 | 2.92 | 1.13 |