| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 5.64 | 5 |
| 2015 | 5.6 | 6 |
| 2014 | 5.86 | 4 |
| 2013 | 5.75 | 5 |
| 2012 | 5.72 | 4 |
| 2011 | 5.88 | 4 |
| 2010 | 6.23 | 3 |
| 2009 | 6.72 | 4 |
| 2008 | 6.5 | 4 |
| 2007 | 6.68 | 4 |
| 2006 | 7.41 | 3 |
| 2005 | 7.57 | 3 |
| 2004 | 8.14 | 2 |
| 2003 | 8.46 | 4 |
| 2002 | 8.26 | 5 |
| 2001 | 7.29 | 5 |
| 2000 | 7.07 | 6 |
| 1999 | 7.34 | 7 |
| 1998 | 7.86 | 5 |
| 1997 | 8.41 | 4 |
| 1996 | 8.68 | 4 |
| 1995 | 8.86 | 6 |
| 1994 | 11.62 | 5 |
| 1993 | 13.26 | 5 |
| 1992 | 12.47 | 3 |
| 1991 | 17.68 | 2 |
| 1990 | 13.78 | 6 |
| 1989 | 13.6 | 3 |
| 1988 | 17.09 | 3 |
| 1987 | 16.9 | 3 |
| 1986 | 14.77 | 3 |