| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.41 | 0.48 | 0.39 |
| 2024 | 0.44 | 0.53 | 0.37 |
| 2023 | 0.61 | 0.76 | 0.43 |
| 2022 | 0.58 | 0.84 | 0.44 |
| 2021 | 0.67 | 0.89 | 0.58 |
| 2020 | 0.69 | 0.78 | 0.62 |
| 2019 | 0.81 | 0.97 | 0.72 |
| 2018 | 0.86 | 1 | 0.69 |
| 2017 | 1.17 | 1.5 | 0.96 |
| 2016 | 1.18 | 1.49 | 1.06 |
| 2015 | 1.52 | 2.26 | 0.93 |
| 2014 | 0.67 | 1.2 | 0.47 |
| 2013 | 0.92 | 1.83 | 0.49 |
| 2012 | 1.04 | 1.69 | 0.88 |
| 2011 | 1.2 | 1.47 | 0.96 |
| 2010 | 1.52 | 1.87 | 1.25 |
| 2009 | 1.74 | 2.24 | 1.28 |
| 2008 | 1.97 | 4.2 | 1.12 |
| 2007 | 3.59 | 5.37 | 1.72 |
| 2006 | 1.39 | 1.76 | 1.2 |
| 2005 | 1.27 | 1.62 | 0.76 |
| 2004 | 1.84 | 3.5 | 0.86 |