| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 64.4 | 109 |
| 2015 | 64.3 | 112 |
| 2014 | 64.1 | 113 |
| 2013 | 63.9 | 116 |
| 2012 | 63.7 | 117 |
| 2011 | 63.4 | 118 |
| 2010 | 63.2 | 117 |
| 2009 | 62.9 | 117 |
| 2008 | 62.6 | 117 |
| 2007 | 62.4 | 117 |
| 2006 | 62.1 | 117 |
| 2005 | 61.8 | 116 |
| 2004 | 61.5 | 113 |
| 2003 | 61.2 | 111 |
| 2002 | 60.8 | 108 |
| 2001 | 60.5 | 108 |
| 2000 | 60.3 | 107 |
| 1999 | 60 | 107 |
| 1998 | 59.7 | 105 |
| 1997 | 59.5 | 103 |
| 1996 | 59.2 | 103 |
| 1995 | 59 | 101 |
| 1994 | 58.7 | 101 |
| 1993 | 58.4 | 100 |
| 1992 | 58.1 | 101 |
| 1991 | 57.8 | 100 |
| 1990 | 57.5 | 98 |
| 1989 | 57.2 | 99 |
| 1988 | 56.9 | 100 |
| 1987 | 56.5 | 102 |
| 1986 | 56.2 | 102 |