| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 64.7 | 105 |
| 2015 | 65 | 102 |
| 2014 | 65.6 | 96 |
| 2013 | 66 | 86 |
| 2012 | 66.5 | 80 |
| 2011 | 66.9 | 74 |
| 2010 | 67.3 | 65 |
| 2009 | 67.6 | 59 |
| 2008 | 67.8 | 52 |
| 2007 | 67.9 | 46 |
| 2006 | 68 | 43 |
| 2005 | 68.1 | 38 |
| 2004 | 68 | 36 |
| 2003 | 67.8 | 38 |
| 2002 | 67.7 | 40 |
| 2001 | 67.5 | 41 |
| 2000 | 67.4 | 40 |
| 1999 | 67.1 | 41 |
| 1998 | 66.8 | 44 |
| 1997 | 66.5 | 46 |
| 1996 | 66.1 | 47 |
| 1995 | 65.8 | 49 |
| 1994 | 65.7 | 48 |
| 1993 | 65.7 | 47 |
| 1992 | 65.8 | 47 |
| 1991 | 65.9 | 44 |
| 1990 | 66.2 | 39 |
| 1989 | 66.2 | 37 |
| 1988 | 66.3 | 35 |
| 1987 | 66.3 | 33 |
| 1986 | 66.4 | 31 |