| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.33 | 0.38 | 0.28 |
| 2024 | 0.38 | 0.42 | 0.33 |
| 2023 | 0.52 | 0.7 | 0.36 |
| 2022 | 0.59 | 0.66 | 0.52 |
| 2021 | 0.75 | 0.95 | 0.57 |
| 2020 | 0.64 | 0.77 | 0.56 |
| 2019 | 0.64 | 0.71 | 0.54 |
| 2018 | 0.74 | 0.99 | 0.55 |
| 2017 | 1.1 | 1.33 | 0.92 |
| 2016 | 1.44 | 1.67 | 1.3 |
| 2015 | 1.64 | 2.45 | 1.25 |
| 2014 | 1.27 | 1.42 | 1.12 |
| 2013 | 1.45 | 1.76 | 1.22 |
| 2012 | 1.17 | 1.35 | 0.92 |
| 2011 | 1.9 | 2.9 | 0.98 |
| 2010 | 2.17 | 2.92 | 1.57 |
| 2009 | 1.64 | 2.27 | 0.94 |
| 2008 | 1.77 | 3.27 | 0.77 |
| 2007 | 2.91 | 3.79 | 2.28 |
| 2006 | 2 | 2.67 | 1.28 |
| 2005 | 0.77 | 1.3 | 0.45 |
| 2004 | 0.8 | 1.37 | 0.53 |