| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 4.83 | 9 |
| 2014 | 3.59 | 18 |
| 2013 | 3.27 | 23 |
| 2012 | 3.41 | 20 |
| 2011 | 3.5 | 16 |
| 2010 | 3.76 | 16 |
| 2009 | 3.97 | 17 |
| 2008 | 3.01 | 29 |
| 2007 | 3.59 | 15 |
| 2006 | 3.54 | 16 |
| 2005 | 4.34 | 12 |
| 2004 | 5.8 | 4 |
| 2003 | 6.54 | 7 |
| 2002 | 7.4 | 6 |
| 2001 | 7.7 | 4 |
| 2000 | 7.15 | 5 |
| 1999 | 7.59 | 6 |
| 1998 | 8.8 | 4 |
| 1997 | 8.09 | 5 |
| 1996 | 10.29 | 3 |
| 1995 | 13.58 | 3 |
| 1994 | 13.26 | 4 |
| 1993 | 12.44 | 6 |
| 1992 | 31.79 | 1 |
| 1991 | 117.39 | 1 |
| 1990 | 48.71 | 2 |
| 1989 | 8.54 | 7 |
| 1988 | 8.24 | 8 |
| 1987 | 5.98 | 13 |
| 1986 | 7.24 | 8 |