| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.43 | 0.46 | 0.41 |
| 2024 | 0.5 | 0.6 | 0.38 |
| 2023 | 0.37 | 0.42 | 0.31 |
| 2022 | 0.37 | 0.48 | 0.28 |
| 2021 | 0.38 | 0.52 | 0.29 |
| 2020 | 0.37 | 0.45 | 0.3 |
| 2019 | 0.66 | 0.88 | 0.42 |
| 2018 | 0.87 | 1.04 | 0.72 |
| 2017 | 1.14 | 1.26 | 0.98 |
| 2016 | 1.08 | 1.31 | 0.97 |
| 2015 | 1.58 | 2.51 | 0.96 |
| 2014 | 0.66 | 1.31 | 0.54 |
| 2013 | 0.78 | 0.94 | 0.66 |
| 2012 | 0.75 | 0.82 | 0.64 |
| 2011 | 1.05 | 1.59 | 0.71 |
| 2010 | 1.85 | 2.62 | 1.27 |
| 2009 | 2.19 | 2.87 | 1.77 |
| 2008 | 2.04 | 3.09 | 1.21 |
| 2007 | 2.47 | 3.25 | 1.28 |
| 2006 | 1.33 | 1.8 | 1.05 |
| 2005 | 1.53 | 1.91 | 1.14 |
| 2004 | 2.43 | 4.21 | 1.33 |