| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 25.05 | 39 |
| 2015 | 24.8 | 38 |
| 2014 | 24.25 | 38 |
| 2013 | 23.77 | 34 |
| 2012 | 23.34 | 32 |
| 2011 | 22.92 | 29 |
| 2010 | 22.47 | 27 |
| 2009 | 22.19 | 21 |
| 2008 | 22.02 | 19 |
| 2007 | 21.98 | 16 |
| 2006 | 22.07 | 15 |
| 2005 | 22.26 | 12 |
| 2004 | 22.81 | 13 |
| 2003 | 23.53 | 15 |
| 2002 | 24.37 | 16 |
| 2001 | 25.22 | 15 |
| 2000 | 26.09 | 17 |
| 1999 | 27.1 | 18 |
| 1998 | 28.06 | 21 |
| 1997 | 29.01 | 22 |
| 1996 | 30.09 | 26 |
| 1995 | 31.34 | 29 |
| 1994 | 31.95 | 29 |
| 1993 | 32.6 | 29 |
| 1992 | 33.15 | 30 |
| 1991 | 33.48 | 31 |
| 1990 | 33.53 | 31 |
| 1989 | 33.68 | 30 |
| 1988 | 33.64 | 29 |
| 1987 | 33.52 | 27 |
| 1986 | 33.36 | 26 |