| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 64.7 | 104 |
| 2015 | 65 | 103 |
| 2014 | 65.6 | 93 |
| 2013 | 66.2 | 82 |
| 2012 | 66.8 | 71 |
| 2011 | 67.5 | 63 |
| 2010 | 68.1 | 52 |
| 2009 | 68.4 | 44 |
| 2008 | 68.7 | 40 |
| 2007 | 68.9 | 32 |
| 2006 | 69.1 | 27 |
| 2005 | 69.2 | 25 |
| 2004 | 69.2 | 22 |
| 2003 | 69 | 21 |
| 2002 | 68.8 | 21 |
| 2001 | 68.4 | 23 |
| 2000 | 68 | 27 |
| 1999 | 67.6 | 34 |
| 1998 | 67 | 39 |
| 1997 | 66.4 | 48 |
| 1996 | 65.7 | 52 |
| 1995 | 64.9 | 57 |
| 1994 | 64.2 | 63 |
| 1993 | 63.5 | 69 |
| 1992 | 62.9 | 71 |
| 1991 | 62.2 | 73 |
| 1990 | 61.4 | 76 |
| 1989 | 60.9 | 77 |
| 1988 | 60.4 | 77 |
| 1987 | 59.9 | 80 |
| 1986 | 59.6 | 80 |