| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 28.77 | 58 |
| 2015 | 28.15 | 72 |
| 2014 | 27.61 | 78 |
| 2013 | 27.64 | 79 |
| 2012 | 26.74 | 89 |
| 2011 | 26.39 | 95 |
| 2010 | 26.14 | 96 |
| 2009 | 26.43 | 93 |
| 2008 | 25.96 | 102 |
| 2007 | 25.74 | 102 |
| 2006 | 25.4 | 102 |
| 2005 | 24.59 | 111 |
| 2004 | 24.02 | 118 |
| 2003 | 23.74 | 113 |
| 2002 | 24.04 | 111 |
| 2001 | 23.77 | 114 |
| 2000 | 23.31 | 111 |
| 1999 | 23.5 | 112 |
| 1998 | 23.83 | 110 |
| 1997 | 23 | 115 |
| 1996 | 22.81 | 114 |
| 1995 | 24.56 | 105 |
| 1994 | 24.33 | 92 |
| 1993 | 23.82 | 94 |
| 1992 | 22.48 | 94 |
| 1991 | 21.74 | 98 |
| 1990 | 20.7 | 98 |
| 1989 | 20.29 | 87 |
| 1988 | 20.42 | 85 |
| 1987 | 20.05 | 83 |
| 1986 | 20.83 | 75 |