| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 24.95 | 25 |
| 2014 | 27.25 | 19 |
| 2013 | 27.41 | 21 |
| 2012 | 26.6 | 24 |
| 2011 | 27.21 | 23 |
| 2010 | 22.07 | 36 |
| 2009 | 20.86 | 39 |
| 2008 | 22.74 | 40 |
| 2007 | 22.22 | 42 |
| 2006 | 24.2 | 35 |
| 2005 | 23.95 | 38 |
| 2004 | 21.6 | 46 |
| 2003 | 27.11 | 30 |
| 2002 | 24.66 | 39 |
| 2001 | 26.16 | 33 |
| 2000 | 27.42 | 32 |
| 1999 | 27.38 | 34 |
| 1998 | 27.17 | 40 |
| 1997 | 35.4 | 24 |
| 1996 | 38.98 | 21 |
| 1995 | 38.43 | 22 |
| 1994 | 23.96 | 48 |
| 1993 | 23.29 | 47 |
| 1992 | 27.4 | 40 |
| 1991 | 36.64 | 24 |
| 1990 | 33.33 | 24 |
| 1989 | 32.03 | 26 |
| 1988 | 31.69 | 28 |
| 1987 | 30.81 | 27 |
| 1986 | 33.05 | 25 |