| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 61.9 | 129 |
| 2015 | 61.6 | 131 |
| 2014 | 61.3 | 134 |
| 2013 | 60.9 | 134 |
| 2012 | 60.4 | 134 |
| 2011 | 60 | 133 |
| 2010 | 59.7 | 134 |
| 2009 | 59.2 | 135 |
| 2008 | 58.9 | 133 |
| 2007 | 58.5 | 133 |
| 2006 | 58.2 | 134 |
| 2005 | 57.8 | 132 |
| 2004 | 57.3 | 132 |
| 2003 | 56.9 | 132 |
| 2002 | 56.4 | 132 |
| 2001 | 56 | 135 |
| 2000 | 55.6 | 134 |
| 1999 | 55.1 | 133 |
| 1998 | 54.6 | 137 |
| 1997 | 54.1 | 139 |
| 1996 | 53.7 | 139 |
| 1995 | 53.4 | 140 |
| 1994 | 53.1 | 140 |
| 1993 | 53 | 138 |
| 1992 | 52.9 | 136 |
| 1991 | 52.9 | 134 |
| 1990 | 52.9 | 135 |
| 1989 | 52.9 | 130 |
| 1988 | 53 | 130 |
| 1987 | 53.2 | 129 |
| 1986 | 53.4 | 128 |