| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 66.9 | 61 |
| 2015 | 66.8 | 66 |
| 2014 | 66.7 | 70 |
| 2013 | 66.6 | 73 |
| 2012 | 66.5 | 79 |
| 2011 | 66.5 | 82 |
| 2010 | 66.4 | 81 |
| 2009 | 66.2 | 84 |
| 2008 | 66 | 84 |
| 2007 | 65.8 | 85 |
| 2006 | 65.7 | 83 |
| 2005 | 65.6 | 80 |
| 2004 | 65.5 | 77 |
| 2003 | 65.4 | 74 |
| 2002 | 65.3 | 69 |
| 2001 | 65.2 | 66 |
| 2000 | 65.1 | 66 |
| 1999 | 65 | 66 |
| 1998 | 64.8 | 65 |
| 1997 | 64.6 | 64 |
| 1996 | 64.4 | 65 |
| 1995 | 64.3 | 66 |
| 1994 | 64 | 65 |
| 1993 | 63.8 | 64 |
| 1992 | 63.6 | 67 |
| 1991 | 63.4 | 68 |
| 1990 | 63.1 | 68 |
| 1989 | 62.9 | 66 |
| 1988 | 62.6 | 65 |
| 1987 | 62.3 | 66 |
| 1986 | 62 | 67 |