| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2026 | 0 | ||
| 2025 | 0 | ||
| 2024 | 0 | ||
| 2023 | 2.36 | 3.55 | 1.36 |
| 2022 | 2.05 | 4.68 | 0.35 |
| 2021 | 0.46 | 0.72 | 0.27 |
| 2020 | 0.47 | 0.63 | 0.36 |
| 2019 | 1.17 | 2.09 | 0.55 |
| 2018 | 10.94 | 38.12 | 1.51 |
| 2017 | 10.07 | 37.77 | 8.07 |
| 2016 | 8.91 | 12.58 | 7.52 |
| 2015 | 11.56 | 20.06 | 6.51 |
| 2014 | 9.84 | 13.23 | 8.26 |
| 2013 | 9.77 | 11 | 8.52 |
| 2012 | 10.13 | 12.95 | 8.66 |
| 2011 | 9.93 | 11.66 | 8.47 |
| 2010 | 11.35 | 15.46 | 8.46 |
| 2009 | 7.68 | 11.68 | 4.72 |
| 2008 | 8.87 | 17.64 | 3.35 |
| 2007 | 14.27 | 20.85 | 9.11 |
| 2006 | 13.67 | 19.12 | 7.65 |
| 2005 | 6.33 | 8.61 | 3.38 |
| 2004 | 4.93 | 7.87 | 3.06 |
| 2003 | 8.32 | 10.96 | 3.67 |
| 2002 | 13.1 | 20.92 | 7.51 |
| 2001 | 9.49 | 11.5 | 7.22 |
| 2000 | 7.88 | 11.52 | 4.59 |
| 1999 | 4.09 | 5.94 | 3 |
| 1998 | 4.1 | 5.65 | 2.88 |
| 1997 | 3.54 | 4.66 | 2.58 |