| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 61.4 | 134 |
| 2015 | 61.1 | 135 |
| 2014 | 60.8 | 137 |
| 2013 | 60.4 | 137 |
| 2012 | 60 | 136 |
| 2011 | 59.7 | 136 |
| 2010 | 59.4 | 136 |
| 2009 | 59 | 137 |
| 2008 | 58.8 | 135 |
| 2007 | 58.5 | 134 |
| 2006 | 58.2 | 132 |
| 2005 | 58 | 131 |
| 2004 | 57.7 | 130 |
| 2003 | 57.4 | 130 |
| 2002 | 57.1 | 130 |
| 2001 | 56.9 | 128 |
| 2000 | 56.6 | 126 |
| 1999 | 56.3 | 125 |
| 1998 | 56 | 124 |
| 1997 | 55.8 | 124 |
| 1996 | 55.5 | 124 |
| 1995 | 55.3 | 125 |
| 1994 | 55.1 | 125 |
| 1993 | 54.8 | 125 |
| 1992 | 54.6 | 123 |
| 1991 | 54.4 | 123 |
| 1990 | 54.3 | 123 |
| 1989 | 54.2 | 121 |
| 1988 | 54.1 | 122 |
| 1987 | 54 | 122 |
| 1986 | 53.9 | 121 |