| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2024 | 0 | ||
| 2023 | 0 | ||
| 2022 | 0 | ||
| 2021 | 0.3 | 0.37 | 0.26 |
| 2020 | 0.28 | 0.34 | 0.25 |
| 2019 | 0.29 | 0.36 | 0.25 |
| 2018 | 0.33 | 0.41 | 0.27 |
| 2017 | 0.47 | 0.61 | 0.34 |
| 2016 | 0.39 | 0.49 | 0.31 |
| 2015 | 0.62 | 0.93 | 0.41 |
| 2014 | 0.31 | 0.68 | 0.22 |
| 2013 | 0.29 | 0.4 | 0.23 |
| 2012 | 0.47 | 0.65 | 0.32 |
| 2011 | 0.99 | 1.67 | 0.54 |
| 2010 | 1.11 | 1.37 | 0.82 |
| 2009 | 0.92 | 1.07 | 0.76 |
| 2008 | 1.24 | 3.49 | 0.5 |
| 2007 | 6.16 | 14.64 | 1.93 |
| 2006 | 1.77 | 2.18 | 1.37 |
| 2005 | 1.21 | 1.51 | 0.87 |
| 2004 | 1.78 | 3.25 | 0.95 |