| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.43 | 1.58 | 1.31 |
| 2024 | 1.27 | 1.76 | 0.94 |
| 2023 | 1.45 | 1.73 | 1.2 |
| 2022 | 1.35 | 1.7 | 1.12 |
| 2021 | 1.59 | 1.96 | 1.38 |
| 2020 | 1.52 | 1.84 | 1.2 |
| 2019 | 1.42 | 1.76 | 1.26 |
| 2018 | 1.66 | 2.03 | 1.25 |
| 2017 | 2.25 | 3.07 | 1.76 |
| 2016 | 2.76 | 3.67 | 2.09 |
| 2015 | 4.07 | 4.88 | 2.93 |
| 2014 | 2.58 | 3.48 | 1.85 |
| 2013 | 2.03 | 2.86 | 1.55 |
| 2012 | 1.9 | 2.34 | 1.32 |
| 2011 | 2.98 | 3.74 | 2.02 |
| 2010 | 3.45 | 4.51 | 2.43 |
| 2009 | 2.77 | 3.77 | 1.91 |
| 2008 | 3.24 | 6.75 | 1.3 |
| 2007 | 7.88 | 13.06 | 4.71 |
| 2006 | 4.9 | 6.54 | 2.87 |
| 2005 | 3.08 | 3.75 | 2.3 |
| 2004 | 3.72 | 4.94 | 2.9 |
| 2003 | 3.78 | 4.57 | 2.71 |
| 2002 | 5.74 | 10.88 | 3.66 |
| 2001 | 11.31 | 14.01 | 8.89 |
| 2000 | 12.7 | 16.17 | 7.13 |
| 1999 | 5.99 | 9.67 | 2.96 |
| 1998 | 5.63 | 7.14 | 4.21 |
| 1997 | 7.15 | 11.04 | 4.7 |