| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2026 | 2.78 | 3.16 | 2.44 |
| 2025 | 2.82 | 3.49 | 2.39 |
| 2024 | 3.49 | 5.41 | 2.48 |
| 2023 | 6.1 | 8.46 | 4.8 |
| 2022 | 5.64 | 9.37 | 2.77 |
| 2021 | 2.53 | 6.33 | 2.02 |
| 2020 | 2.88 | 3.79 | 2.48 |
| 2019 | 3.41 | 4.78 | 2.73 |
| 2018 | 4.04 | 5.25 | 3.25 |
| 2017 | 7.16 | 11.67 | 4.82 |
| 2016 | 10.84 | 13.06 | 8.32 |
| 2015 | 11.88 | 23.15 | 5.98 |
| 2014 | 6.31 | 7.69 | 5.39 |
| 2013 | 5.6 | 6.65 | 4.37 |
| 2012 | 5.02 | 6.67 | 3.73 |
| 2011 | 6.95 | 9.22 | 4.65 |
| 2010 | 7.92 | 9.96 | 6.27 |
| 2009 | 9.46 | 14.2 | 6.71 |
| 2008 | 9.48 | 18.73 | 3.6 |
| 2007 | 13.68 | 21.03 | 7.51 |
| 2006 | 4.45 | 8.23 | 2.08 |
| 2005 | 2.3 | 3.15 | 1.43 |
| 2004 | 2.95 | 4.18 | 2.33 |
| 2003 | 4.44 | 5.5 | 2.82 |
| 2002 | 5.95 | 7.16 | 4.65 |
| 2001 | 6.73 | 7.99 | 4.59 |
| 2000 | 7.59 | 9.03 | 5.44 |
| 1999 | 8.3 | 10.3 | 5.68 |
| 1998 | 10.31 | 13.8 | 6.99 |