| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 4 | 4.51 | 3.6 |
| 2024 | 3.71 | 5.15 | 2.84 |
| 2023 | 4.29 | 5.31 | 3.57 |
| 2022 | 3.88 | 4.8 | 3.08 |
| 2021 | 4.7 | 5.84 | 3.96 |
| 2020 | 6.25 | 9.01 | 4.38 |
| 2019 | 9.21 | 16.82 | 5.19 |
| 2018 | 2.41 | 4.77 | 1.59 |
| 2017 | 3.17 | 3.82 | 2.59 |
| 2016 | 3.71 | 4.68 | 2.9 |
| 2015 | 5.55 | 9.92 | 3.12 |
| 2014 | 4.77 | 6.15 | 2.72 |
| 2013 | 2.47 | 3.1 | 1.98 |
| 2012 | 2.55 | 3.36 | 1.7 |
| 2011 | 3.44 | 5.07 | 2.52 |
| 2010 | 2.99 | 3.8 | 2.4 |
| 2009 | 2.68 | 3.38 | 1.91 |
| 2008 | 2.73 | 4.81 | 1.2 |
| 2007 | 4.16 | 6.35 | 2.7 |
| 2006 | 1.59 | 2.97 | 0.79 |
| 2005 | 0.75 | 1.03 | 0.47 |
| 2004 | 1.12 | 1.45 | 0.82 |
| 2003 | 1.23 | 1.48 | 0.92 |
| 2002 | 2.14 | 2.52 | 1.9 |
| 2001 | 3.28 | 4.78 | 2.32 |
| 2000 | 5.58 | 7.03 | 4.15 |
| 1999 | 4.64 | 6.45 | 3.16 |
| 1998 | 4.62 | 6.13 | 3.34 |
| 1997 | 5.06 | 7.18 | 3.84 |