| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 60 | 140 |
| 2015 | 59.7 | 141 |
| 2014 | 59.4 | 142 |
| 2013 | 59.1 | 142 |
| 2012 | 58.8 | 144 |
| 2011 | 58.5 | 144 |
| 2010 | 58.3 | 142 |
| 2009 | 58.1 | 141 |
| 2008 | 57.9 | 140 |
| 2007 | 57.8 | 138 |
| 2006 | 57.7 | 136 |
| 2005 | 57.6 | 135 |
| 2004 | 57.5 | 131 |
| 2003 | 57.4 | 131 |
| 2002 | 57.2 | 129 |
| 2001 | 57.2 | 126 |
| 2000 | 57.1 | 124 |
| 1999 | 57 | 122 |
| 1998 | 56.8 | 121 |
| 1997 | 56.6 | 121 |
| 1996 | 56.5 | 118 |
| 1995 | 56.3 | 117 |
| 1994 | 56 | 116 |
| 1993 | 55.8 | 115 |
| 1992 | 55.5 | 117 |
| 1991 | 55.3 | 117 |
| 1990 | 55 | 119 |
| 1989 | 54.8 | 117 |
| 1988 | 54.5 | 118 |
| 1987 | 54.3 | 119 |
| 1986 | 54.1 | 120 |