| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 65.4 | 94 |
| 2015 | 65.3 | 99 |
| 2014 | 65.1 | 101 |
| 2013 | 65 | 103 |
| 2012 | 64.9 | 106 |
| 2011 | 64.7 | 108 |
| 2010 | 64.4 | 108 |
| 2009 | 64.1 | 108 |
| 2008 | 63.8 | 109 |
| 2007 | 63.4 | 108 |
| 2006 | 63 | 109 |
| 2005 | 62.6 | 108 |
| 2004 | 62.2 | 107 |
| 2003 | 61.9 | 105 |
| 2002 | 61.5 | 105 |
| 2001 | 61.1 | 105 |
| 2000 | 60.8 | 104 |
| 1999 | 60.4 | 102 |
| 1998 | 60.2 | 101 |
| 1997 | 59.9 | 99 |
| 1996 | 59.6 | 98 |
| 1995 | 59.3 | 97 |
| 1994 | 58.9 | 98 |
| 1993 | 58.5 | 99 |
| 1992 | 58.1 | 100 |
| 1991 | 57.8 | 101 |
| 1990 | 57.5 | 100 |
| 1989 | 57.1 | 101 |
| 1988 | 56.8 | 101 |
| 1987 | 56.6 | 101 |
| 1986 | 56.3 | 101 |