| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 32.86 | 30 |
| 2015 | 34.53 | 32 |
| 2014 | 33.63 | 44 |
| 2013 | 33.25 | 46 |
| 2012 | 32.98 | 49 |
| 2011 | 32.89 | 51 |
| 2010 | 33.38 | 49 |
| 2009 | 33.59 | 45 |
| 2008 | 32.26 | 59 |
| 2007 | 29.89 | 74 |
| 2006 | 29.86 | 72 |
| 2005 | 23.16 | 117 |
| 2004 | 25.96 | 99 |
| 2003 | 23.5 | 115 |
| 2002 | 22.05 | 123 |
| 2001 | 22.64 | 122 |
| 2000 | 23.13 | 115 |
| 1999 | 24.31 | 108 |
| 1998 | 26.17 | 94 |
| 1997 | 26.11 | 97 |
| 1996 | 30.48 | 66 |
| 1995 | 27.8 | 91 |
| 1994 | 26.43 | 81 |
| 1993 | 34.47 | 40 |
| 1992 | 35.81 | 40 |
| 1991 | 36.57 | 36 |
| 1990 | 32.96 | 50 |
| 1989 | 32.56 | 49 |
| 1988 | 35.79 | 30 |
| 1987 | 38.26 | 23 |