| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 26.56 | 1 |
| 2015 | 26.02 | 1 |
| 2014 | 25.35 | 1 |
| 2013 | 24.63 | 1 |
| 2012 | 23.88 | 1 |
| 2011 | 23.16 | 1 |
| 2010 | 22.5 | 1 |
| 2009 | 21.83 | 1 |
| 2008 | 21.24 | 1 |
| 2007 | 20.7 | 1 |
| 2006 | 20.18 | 1 |
| 2005 | 19.65 | 1 |
| 2004 | 19.1 | 2 |
| 2003 | 18.56 | 2 |
| 2002 | 18.03 | 2 |
| 2001 | 17.51 | 2 |
| 2000 | 16.98 | 3 |
| 1999 | 16.45 | 5 |
| 1998 | 15.91 | 8 |
| 1997 | 15.37 | 12 |
| 1996 | 14.83 | 14 |
| 1995 | 14.3 | 16 |
| 1994 | 13.78 | 19 |
| 1993 | 13.27 | 19 |
| 1992 | 12.78 | 21 |
| 1991 | 12.31 | 23 |
| 1990 | 11.87 | 24 |
| 1989 | 11.45 | 26 |
| 1988 | 11.06 | 27 |
| 1987 | 10.71 | 28 |
| 1986 | 10.4 | 31 |