| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 57.7 | 151 |
| 2015 | 57.4 | 151 |
| 2014 | 57.3 | 150 |
| 2013 | 57.1 | 150 |
| 2012 | 56.8 | 151 |
| 2011 | 56.7 | 151 |
| 2010 | 56.7 | 150 |
| 2009 | 56.5 | 150 |
| 2008 | 56.3 | 149 |
| 2007 | 56 | 148 |
| 2006 | 55.8 | 149 |
| 2005 | 55.6 | 150 |
| 2004 | 55.5 | 147 |
| 2003 | 55.4 | 145 |
| 2002 | 55.3 | 145 |
| 2001 | 55.1 | 144 |
| 2000 | 54.8 | 145 |
| 1999 | 55 | 136 |
| 1998 | 55.1 | 130 |
| 1997 | 55.2 | 127 |
| 1996 | 55.2 | 126 |
| 1995 | 55.1 | 126 |
| 1994 | 55.4 | 121 |
| 1993 | 55.6 | 117 |
| 1992 | 55.8 | 113 |
| 1991 | 55.8 | 112 |
| 1990 | 55.8 | 112 |
| 1989 | 55.5 | 112 |
| 1988 | 55.2 | 114 |
| 1987 | 54.8 | 114 |
| 1986 | 54.5 | 116 |