| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 25.09 | 40 |
| 2015 | 24.16 | 36 |
| 2014 | 23.38 | 31 |
| 2013 | 22.51 | 29 |
| 2012 | 21.66 | 21 |
| 2011 | 21.02 | 11 |
| 2010 | 20.68 | 10 |
| 2009 | 20.45 | 9 |
| 2008 | 20.43 | 9 |
| 2007 | 20.6 | 9 |
| 2006 | 20.93 | 10 |
| 2005 | 21.37 | 9 |
| 2004 | 22.11 | 10 |
| 2003 | 23.1 | 11 |
| 2002 | 24.24 | 14 |
| 2001 | 25.35 | 16 |
| 2000 | 26.32 | 18 |
| 1999 | 27.63 | 22 |
| 1998 | 28.79 | 25 |
| 1997 | 29.82 | 28 |
| 1996 | 30.9 | 30 |
| 1995 | 32.16 | 32 |
| 1994 | 32.9 | 33 |
| 1993 | 33.55 | 34 |
| 1992 | 34.07 | 35 |
| 1991 | 34.34 | 35 |
| 1990 | 34.29 | 34 |
| 1989 | 34.37 | 33 |
| 1988 | 34.3 | 32 |
| 1987 | 34.11 | 30 |
| 1986 | 33.78 | 28 |