| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 21.54 | 16 |
| 2015 | 21.25 | 11 |
| 2014 | 20.8 | 7 |
| 2013 | 20.37 | 7 |
| 2012 | 19.97 | 5 |
| 2011 | 19.63 | 5 |
| 2010 | 19.33 | 5 |
| 2009 | 19.2 | 5 |
| 2008 | 19.2 | 5 |
| 2007 | 19.31 | 4 |
| 2006 | 19.49 | 2 |
| 2005 | 19.67 | 2 |
| 2004 | 20.23 | 2 |
| 2003 | 20.87 | 3 |
| 2002 | 21.58 | 5 |
| 2001 | 22.32 | 5 |
| 2000 | 23.12 | 7 |
| 1999 | 23.83 | 7 |
| 1998 | 24.5 | 8 |
| 1997 | 25.16 | 9 |
| 1996 | 25.89 | 10 |
| 1995 | 26.74 | 14 |
| 1994 | 27.58 | 18 |
| 1993 | 28.51 | 18 |
| 1992 | 29.43 | 20 |
| 1991 | 30.16 | 23 |
| 1990 | 30.59 | 23 |
| 1989 | 31.16 | 22 |
| 1988 | 31.5 | 21 |
| 1987 | 31.69 | 18 |
| 1986 | 31.92 | 19 |