| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.61 | 1.79 | 0.33 |
| 2024 | 0.32 | 0.5 | 0.24 |
| 2023 | 0.42 | 0.53 | 0.31 |
| 2022 | 0.44 | 0.63 | 0.36 |
| 2021 | 0.45 | 0.52 | 0.38 |
| 2020 | 0.59 | 0.73 | 0.49 |
| 2019 | 0.71 | 0.91 | 0.59 |
| 2018 | 0.69 | 0.96 | 0.54 |
| 2017 | 0.98 | 1.26 | 0.8 |
| 2016 | 1.15 | 1.56 | 0.96 |
| 2015 | 1.84 | 3.07 | 1.31 |
| 2014 | 0.84 | 1.56 | 0.67 |
| 2013 | 1.08 | 1.63 | 0.79 |
| 2012 | 1.42 | 1.76 | 1.11 |
| 2011 | 1.6 | 2.15 | 1.05 |
| 2010 | 2 | 2.71 | 1.47 |
| 2009 | 4.11 | 8.18 | 1.47 |
| 2008 | 10.65 | 47.21 | 1.01 |
| 2007 | 9.34 | 18.11 | 2.27 |
| 2006 | 1.7 | 2.64 | 1.08 |
| 2005 | 1.33 | 1.54 | 1.14 |
| 2004 | 1.86 | 2.62 | 1.35 |
| 2003 | 2.83 | 4.06 | 1.84 |
| 2002 | 3.96 | 4.71 | 2.61 |