| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2024 | 0.55 | 0.74 | 0.4 |
| 2023 | 0.56 | 0.66 | 0.41 |
| 2022 | 0.55 | 0.69 | 0.41 |
| 2021 | 0.56 | 0.97 | 0.36 |
| 2020 | 0.31 | 0.53 | 0.22 |
| 2019 | 0.37 | 0.44 | 0.29 |
| 2018 | 0.6 | 0.96 | 0.29 |
| 2017 | 0.82 | 1.07 | 0.65 |
| 2016 | 1.4 | 2.12 | 0.95 |
| 2015 | 3.89 | 7.25 | 1.93 |
| 2014 | 2.64 | 4.21 | 1.44 |
| 2013 | 3.25 | 4.98 | 2.26 |
| 2012 | 6.97 | 12.62 | 2.47 |
| 2011 | 16.77 | 33.24 | 8.82 |
| 2010 | 11.29 | 27.34 | 5.34 |
| 2009 | 6.19 | 8.23 | 4.69 |
| 2008 | 15.23 | 40.98 | 3.2 |
| 2007 | 14.16 | 31.81 | 5.62 |
| 2006 | 2.63 | 3.32 | 1.61 |
| 2005 | 2.74 | 4 | 1.77 |
| 2004 | 3.98 | 6.43 | 2.39 |