| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 64.2 | 113 |
| 2015 | 64.2 | 113 |
| 2014 | 64.1 | 114 |
| 2013 | 63.9 | 115 |
| 2012 | 63.8 | 116 |
| 2011 | 63.7 | 114 |
| 2010 | 63.5 | 114 |
| 2009 | 63.4 | 114 |
| 2008 | 63.2 | 114 |
| 2007 | 63 | 113 |
| 2006 | 62.8 | 110 |
| 2005 | 62.7 | 107 |
| 2004 | 62.6 | 104 |
| 2003 | 62.5 | 103 |
| 2002 | 62.4 | 99 |
| 2001 | 62.4 | 96 |
| 2000 | 62.4 | 91 |
| 1999 | 62.3 | 86 |
| 1998 | 62.4 | 84 |
| 1997 | 62.4 | 79 |
| 1996 | 62.5 | 78 |
| 1995 | 62.5 | 73 |
| 1994 | 62.5 | 73 |
| 1993 | 62.4 | 73 |
| 1992 | 62.4 | 73 |
| 1991 | 62.3 | 72 |
| 1990 | 62.3 | 72 |
| 1989 | 62.3 | 71 |
| 1988 | 62.2 | 69 |
| 1987 | 62.3 | 67 |
| 1986 | 62.3 | 65 |