| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 27.4 | 17 |
| 2015 | 27.74 | 18 |
| 2014 | 24.26 | 26 |
| 2013 | 19.71 | 46 |
| 2012 | 19.75 | 43 |
| 2011 | 18.26 | 47 |
| 2010 | 21.65 | 38 |
| 2009 | 25.78 | 30 |
| 2008 | 25.19 | 28 |
| 2007 | 25.57 | 29 |
| 2006 | 22.94 | 41 |
| 2005 | 30.52 | 24 |
| 2004 | 35.53 | 15 |
| 2003 | 37.07 | 18 |
| 2002 | 35.13 | 21 |
| 2001 | 35.79 | 20 |
| 2000 | 36.68 | 16 |
| 1999 | 35.52 | 21 |
| 1998 | 33.09 | 28 |
| 1997 | 33.38 | 28 |
| 1996 | 36.24 | 25 |
| 1995 | 37.43 | 24 |
| 1994 | 36.95 | 24 |
| 1993 | 38 | 24 |
| 1992 | 37.47 | 22 |
| 1991 | 37.52 | 19 |
| 1990 | 29.62 | 34 |
| 1989 | 31.91 | 27 |
| 1988 | 32.69 | 24 |
| 1987 | 32.31 | 25 |
| 1986 | 26.63 | 36 |