| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 69.6 | 25 |
| 2015 | 69.8 | 28 |
| 2014 | 70.1 | 27 |
| 2013 | 70.2 | 28 |
| 2012 | 70.2 | 27 |
| 2011 | 70.2 | 26 |
| 2010 | 70.3 | 25 |
| 2009 | 70.1 | 27 |
| 2008 | 69.8 | 27 |
| 2007 | 69.5 | 25 |
| 2006 | 69.2 | 26 |
| 2005 | 68.8 | 32 |
| 2004 | 68.6 | 31 |
| 2003 | 68.4 | 29 |
| 2002 | 68.3 | 28 |
| 2001 | 68.2 | 27 |
| 2000 | 68.3 | 20 |
| 1999 | 68.4 | 18 |
| 1998 | 68.5 | 13 |
| 1997 | 68.6 | 11 |
| 1996 | 68.7 | 9 |
| 1995 | 68.8 | 9 |
| 1994 | 69 | 9 |
| 1993 | 69.2 | 8 |
| 1992 | 69.3 | 7 |
| 1991 | 69.3 | 6 |
| 1990 | 69.3 | 7 |
| 1989 | 69.2 | 7 |
| 1988 | 69.1 | 8 |
| 1987 | 68.9 | 8 |
| 1986 | 68.6 | 8 |