| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.97 | 2.37 | 1.73 |
| 2024 | 1.45 | 2.76 | 1.03 |
| 2023 | 2.16 | 3.04 | 1.72 |
| 2022 | 1.1 | 2.27 | 0.79 |
| 2021 | 0.89 | 1.02 | 0.8 |
| 2020 | 1.06 | 1.34 | 0.85 |
| 2019 | 1.08 | 1.67 | 0.79 |
| 2018 | 1.22 | 1.96 | 0.7 |
| 2017 | 2.59 | 2.92 | 1.6 |
| 2016 | 2.65 | 3.12 | 2.13 |
| 2015 | 3.67 | 6.92 | 1.89 |
| 2014 | 3.99 | 5.99 | 2.84 |
| 2013 | 5.91 | 10.41 | 3 |
| 2012 | 5.07 | 6.65 | 3.77 |
| 2011 | 6.04 | 7.38 | 5.38 |
| 2010 | 9.61 | 14.02 | 5.22 |
| 2009 | 6.85 | 11.34 | 2.48 |
| 2008 | 4.66 | 8.49 | 1.97 |
| 2007 | 4.8 | 8.05 | 2.14 |
| 2006 | 2.24 | 3.15 | 1.27 |
| 2005 | 1.83 | 2.89 | 1.11 |
| 2004 | 3.49 | 5.45 | 2.57 |
| 2003 | 4.07 | 5.33 | 2.83 |
| 2002 | 6.07 | 7.01 | 4.82 |
| 2001 | 5.28 | 6.31 | 3.86 |
| 2000 | 5.45 | 6.71 | 4.63 |
| 1999 | 5.8 | 8.68 | 4.02 |
| 1998 | 5.81 | 7.24 | 4.29 |