| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 60.6 | 136 |
| 2015 | 60.9 | 137 |
| 2014 | 61.2 | 136 |
| 2013 | 61.5 | 130 |
| 2012 | 61.8 | 129 |
| 2011 | 62 | 125 |
| 2010 | 62.3 | 123 |
| 2009 | 62.4 | 120 |
| 2008 | 62.4 | 119 |
| 2007 | 62.4 | 118 |
| 2006 | 62.3 | 114 |
| 2005 | 62.1 | 113 |
| 2004 | 62.1 | 108 |
| 2003 | 62.1 | 104 |
| 2002 | 62 | 102 |
| 2001 | 61.9 | 100 |
| 2000 | 61.9 | 95 |
| 1999 | 61.8 | 93 |
| 1998 | 61.7 | 91 |
| 1997 | 61.6 | 88 |
| 1996 | 61.5 | 86 |
| 1995 | 61.3 | 86 |
| 1994 | 61 | 83 |
| 1993 | 60.8 | 85 |
| 1992 | 60.4 | 85 |
| 1991 | 60.1 | 86 |
| 1990 | 59.8 | 85 |
| 1989 | 59.5 | 85 |
| 1988 | 59.3 | 82 |
| 1987 | 59 | 82 |
| 1986 | 58.8 | 82 |