| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.66 | 0.94 | 0.43 |
| 2024 | 0.52 | 0.69 | 0.38 |
| 2023 | 0.82 | 1.47 | 0.58 |
| 2022 | 0.6 | 0.89 | 0.44 |
| 2021 | 0.47 | 0.67 | 0.42 |
| 2020 | 0.56 | 0.67 | 0.49 |
| 2019 | 0.73 | 1.12 | 0.6 |
| 2018 | 0.72 | 0.93 | 0.55 |
| 2017 | 1.6 | 3.27 | 0.75 |
| 2016 | 2.08 | 2.93 | 1.39 |
| 2015 | 2.57 | 5.07 | 1.12 |
| 2014 | 1.17 | 1.47 | 0.88 |
| 2013 | 1.13 | 1.91 | 0.76 |
| 2012 | 0.92 | 1.38 | 0.66 |
| 2011 | 1.7 | 2.47 | 0.81 |
| 2010 | 2.27 | 3.28 | 1.49 |
| 2009 | 2.89 | 3.9 | 1.14 |
| 2008 | 1.54 | 3.19 | 0.81 |
| 2007 | 1.69 | 3.11 | 0.51 |
| 2006 | 0.59 | 0.78 | 0.41 |
| 2005 | 0.46 | 0.65 | 0.35 |
| 2004 | 0.79 | 1.64 | 0.45 |