| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2026 | 5.9 | 6.19 | 5.48 |
| 2025 | 7.2 | 8.99 | 5.8 |
| 2024 | 7.42 | 9.24 | 5.25 |
| 2023 | 6.52 | 11.12 | 3.7 |
| 2022 | 9.17 | 12.22 | 6.51 |
| 2021 | 21.4 | 42.01 | 3.99 |
| 2020 | 4.9 | 7.22 | 3.77 |
| 2019 | 7.72 | 9.18 | 6.32 |
| 2018 | 8.38 | 9.15 | 7.34 |
| 2017 | 8.9 | 10.59 | 7.88 |
| 2016 | 11 | 13.55 | 10 |
| 2015 | 9.47 | 11.94 | 7.43 |
| 2014 | 7.96 | 9.53 | 7 |
| 2013 | 8.88 | 10.58 | 7.61 |
| 2012 | 7.57 | 9.58 | 5.54 |
| 2011 | 7.35 | 9.12 | 5.49 |
| 2010 | 9.85 | 13.4 | 8.23 |
| 2009 | 9.01 | 12.71 | 5.96 |
| 2008 | 7.85 | 16.9 | 3.95 |
| 2007 | 16.78 | 27.02 | 9.51 |
| 2006 | 8.73 | 10.33 | 7.32 |
| 2005 | 4.23 | 7.41 | 2.65 |
| 2004 | 4.88 | 6.32 | 3.82 |
| 2003 | 5.39 | 6.44 | 4.3 |
| 2002 | 6.59 | 8.41 | 5.07 |
| 2001 | 8.99 | 14.97 | 3.93 |
| 2000 | 4.33 | 5.28 | 3.6 |
| 1999 | 3.53 | 6.39 | 1.83 |
| 1998 | 3.28 | 4.42 | 1.9 |