| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.16 | 1.25 | 1.04 |
| 2024 | 1.14 | 1.53 | 0.69 |
| 2023 | 1.29 | 1.63 | 0.99 |
| 2022 | 1.57 | 3.15 | 0.52 |
| 2021 | 0.84 | 1 | 0.71 |
| 2020 | 0.7 | 1.12 | 0.51 |
| 2019 | 0.62 | 0.93 | 0.38 |
| 2018 | 0.56 | 0.87 | 0.31 |
| 2017 | 0.9 | 1.2 | 0.71 |
| 2016 | 1.26 | 1.76 | 0.98 |
| 2015 | 1.27 | 1.96 | 0.78 |
| 2014 | 0.89 | 1.04 | 0.6 |
| 2013 | 0.53 | 0.73 | 0.42 |
| 2012 | 0.64 | 0.89 | 0.45 |
| 2011 | 0.98 | 1.32 | 0.72 |
| 2010 | 1.34 | 1.81 | 0.99 |
| 2009 | 1.01 | 1.9 | 0.49 |
| 2008 | 0.9 | 1.93 | 0.34 |
| 2007 | 1.52 | 2.57 | 0.59 |
| 2006 | 0.71 | 0.96 | 0.52 |
| 2005 | 0.75 | 0.88 | 0.59 |
| 2004 | 1.35 | 2.17 | 0.78 |