| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.52 | 0.58 | 0.45 |
| 2024 | 0.54 | 0.66 | 0.45 |
| 2023 | 0.52 | 0.66 | 0.41 |
| 2022 | 0.45 | 0.66 | 0.32 |
| 2021 | 0.37 | 0.52 | 0.32 |
| 2020 | 0.38 | 0.46 | 0.33 |
| 2019 | 0.45 | 0.55 | 0.38 |
| 2018 | 0.48 | 0.56 | 0.42 |
| 2017 | 0.69 | 0.81 | 0.48 |
| 2016 | 0.74 | 0.94 | 0.68 |
| 2015 | 1.02 | 1.48 | 0.68 |
| 2014 | 0.45 | 0.96 | 0.32 |
| 2013 | 0.44 | 0.59 | 0.33 |
| 2012 | 0.45 | 0.59 | 0.36 |
| 2011 | 0.47 | 0.62 | 0.36 |
| 2010 | 0.76 | 1.03 | 0.51 |
| 2009 | 0.94 | 1.19 | 0.72 |
| 2008 | 1.48 | 3.37 | 0.62 |
| 2007 | 2.86 | 4.33 | 1.32 |
| 2006 | 1.25 | 1.64 | 0.95 |