| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 64.1 | 116 |
| 2015 | 63.8 | 118 |
| 2014 | 63.6 | 118 |
| 2013 | 63.2 | 120 |
| 2012 | 62.8 | 123 |
| 2011 | 62.3 | 123 |
| 2010 | 62 | 125 |
| 2009 | 61.5 | 124 |
| 2008 | 61.2 | 124 |
| 2007 | 60.8 | 124 |
| 2006 | 60.4 | 122 |
| 2005 | 59.9 | 121 |
| 2004 | 59.4 | 122 |
| 2003 | 58.8 | 123 |
| 2002 | 58.3 | 122 |
| 2001 | 57.8 | 122 |
| 2000 | 57.3 | 122 |
| 1999 | 56.9 | 123 |
| 1998 | 56.4 | 123 |
| 1997 | 56.1 | 123 |
| 1996 | 55.7 | 121 |
| 1995 | 55.4 | 121 |
| 1994 | 55.2 | 123 |
| 1993 | 55 | 122 |
| 1992 | 54.8 | 121 |
| 1991 | 54.7 | 121 |
| 1990 | 54.7 | 120 |
| 1989 | 54.6 | 118 |
| 1988 | 54.6 | 116 |
| 1987 | 54.6 | 117 |
| 1986 | 54.6 | 115 |