| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.47 | 0.7 | 0.37 |
| 2024 | 0.37 | 0.53 | 0.24 |
| 2023 | 0.52 | 0.65 | 0.39 |
| 2022 | 0.58 | 0.82 | 0.38 |
| 2021 | 0.54 | 0.85 | 0.35 |
| 2020 | 0.55 | 0.73 | 0.4 |
| 2019 | 0.66 | 0.78 | 0.59 |
| 2018 | 0.64 | 0.85 | 0.52 |
| 2017 | 1.2 | 1.56 | 0.78 |
| 2016 | 1.53 | 2.05 | 1.07 |
| 2015 | 1.74 | 2.5 | 0.8 |
| 2014 | 0.8 | 0.99 | 0.56 |
| 2013 | 0.75 | 0.98 | 0.58 |
| 2012 | 0.86 | 1.08 | 0.65 |
| 2011 | 1.19 | 2.45 | 0.66 |
| 2010 | 9.78 | 35.97 | 1.21 |
| 2009 | 8.22 | 10.69 | 4.16 |
| 2008 | 6.73 | 13.43 | 2.53 |
| 2007 | 10.71 | 17.46 | 3.81 |
| 2006 | 3.63 | 4.94 | 2.67 |
| 2005 | 3.14 | 4.06 | 2.33 |
| 2004 | 3.35 | 5.76 | 1.62 |