| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 72.5 | 10 |
| 2015 | 72.8 | 10 |
| 2014 | 73.1 | 10 |
| 2013 | 73.3 | 10 |
| 2012 | 73.5 | 10 |
| 2011 | 73.6 | 8 |
| 2010 | 73.6 | 8 |
| 2009 | 73.3 | 8 |
| 2008 | 73 | 8 |
| 2007 | 72.8 | 8 |
| 2006 | 72.7 | 8 |
| 2005 | 72.6 | 5 |
| 2004 | 72.5 | 5 |
| 2003 | 72.2 | 6 |
| 2002 | 71.9 | 6 |
| 2001 | 71.6 | 5 |
| 2000 | 71.2 | 5 |
| 1999 | 71.1 | 5 |
| 1998 | 71 | 5 |
| 1997 | 70.9 | 5 |
| 1996 | 71 | 5 |
| 1995 | 71.4 | 2 |
| 1994 | 71.7 | 1 |
| 1993 | 72.1 | 1 |
| 1992 | 72.6 | 1 |
| 1991 | 72.9 | 1 |
| 1990 | 72.9 | 1 |
| 1989 | 72.7 | 1 |
| 1988 | 72.2 | 1 |
| 1987 | 71.5 | 1 |
| 1986 | 70.9 | 1 |