| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.39 | 0.41 | 0.35 |
| 2024 | 0.32 | 0.47 | 0.24 |
| 2023 | 0.39 | 0.53 | 0.27 |
| 2022 | 0.53 | 0.69 | 0.42 |
| 2021 | 0.59 | 0.7 | 0.49 |
| 2020 | 0.77 | 1 | 0.61 |
| 2019 | 1 | 1.67 | 0.8 |
| 2018 | 1.45 | 1.9 | 0.97 |
| 2017 | 1.88 | 2.23 | 1.65 |
| 2016 | 1.84 | 2.19 | 1.56 |
| 2015 | 2.07 | 3.39 | 1.1 |
| 2014 | 1.08 | 1.74 | 0.87 |
| 2013 | 1.19 | 1.48 | 0.95 |
| 2012 | 1.14 | 1.42 | 0.75 |
| 2011 | 1.22 | 1.68 | 0.77 |
| 2010 | 1.73 | 2.23 | 1.31 |
| 2009 | 1.12 | 2.1 | 0.53 |
| 2008 | 1.22 | 3.19 | 0.42 |
| 2007 | 2.91 | 4.19 | 1.47 |
| 2006 | 0.89 | 1.68 | 0.5 |
| 2005 | 0.56 | 0.7 | 0.43 |
| 2004 | 0.74 | 1.34 | 0.46 |