| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 0.57 | 0.65 | 0.5 |
| 2024 | 0.44 | 0.67 | 0.32 |
| 2023 | 0.52 | 0.65 | 0.41 |
| 2022 | 0.59 | 0.7 | 0.51 |
| 2021 | 0.68 | 0.75 | 0.6 |
| 2020 | 0.8 | 0.99 | 0.71 |
| 2019 | 0.85 | 1.19 | 0.7 |
| 2018 | 1.03 | 1.57 | 0.74 |
| 2017 | 1.46 | 1.92 | 1.18 |
| 2016 | 1.67 | 1.95 | 1.4 |
| 2015 | 3.31 | 6.1 | 1.75 |
| 2014 | 1.88 | 4.52 | 1.4 |
| 2013 | 1.82 | 2.62 | 1.36 |
| 2012 | 2.39 | 3.04 | 1.86 |
| 2011 | 3.42 | 4.72 | 2.2 |
| 2010 | 4.41 | 5.61 | 3.63 |
| 2009 | 6.12 | 9.09 | 2.7 |
| 2008 | 4.83 | 9.31 | 2.38 |
| 2007 | 11.92 | 22.01 | 5.61 |
| 2006 | 3.39 | 20.03 | 0.99 |
| 2005 | 1.22 | 1.64 | 0.85 |
| 2004 | 2.95 | 7.25 | 1.45 |
| 2003 | 7.11 | 9.77 | 2.68 |
| 2002 | 12.32 | 16.69 | 8.91 |
| 2001 | 17.07 | 20.7 | 12.48 |
| 2000 | 6.08 | 7.53 | 5.08 |