| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 64.6 | 106 |
| 2015 | 64.6 | 107 |
| 2014 | 64.5 | 108 |
| 2013 | 64.4 | 109 |
| 2012 | 64.3 | 110 |
| 2011 | 64.2 | 111 |
| 2010 | 64.1 | 111 |
| 2009 | 64 | 109 |
| 2008 | 63.9 | 107 |
| 2007 | 63.8 | 107 |
| 2006 | 63.6 | 103 |
| 2005 | 63.5 | 100 |
| 2004 | 63.3 | 98 |
| 2003 | 63.1 | 96 |
| 2002 | 62.9 | 95 |
| 2001 | 62.7 | 90 |
| 2000 | 62.5 | 88 |
| 1999 | 62.3 | 88 |
| 1998 | 62 | 85 |
| 1997 | 61.8 | 85 |
| 1996 | 61.6 | 84 |
| 1995 | 61.3 | 85 |
| 1994 | 60.9 | 87 |
| 1993 | 60.6 | 87 |
| 1992 | 60.2 | 88 |
| 1991 | 59.8 | 89 |
| 1990 | 59.4 | 90 |
| 1989 | 58.9 | 90 |
| 1988 | 58.5 | 90 |
| 1987 | 58 | 91 |
| 1986 | 57.6 | 93 |