| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 43.9 | 16 |
| 2015 | 44.5 | 15 |
| 2014 | 45.3 | 12 |
| 2013 | 46 | 9 |
| 2012 | 46.7 | 7 |
| 2011 | 47.3 | 7 |
| 2010 | 47.8 | 4 |
| 2009 | 47.9 | 4 |
| 2008 | 47.9 | 5 |
| 2007 | 47.8 | 5 |
| 2006 | 47.7 | 6 |
| 2005 | 47.6 | 6 |
| 2004 | 47.8 | 5 |
| 2003 | 48.1 | 5 |
| 2002 | 48.3 | 5 |
| 2001 | 48.5 | 5 |
| 2000 | 48.6 | 6 |
| 1999 | 48.5 | 6 |
| 1998 | 48.3 | 6 |
| 1997 | 48.2 | 6 |
| 1996 | 48 | 7 |
| 1995 | 47.8 | 8 |
| 1994 | 47.9 | 8 |
| 1993 | 48 | 8 |
| 1992 | 48 | 8 |
| 1991 | 48 | 9 |
| 1990 | 48 | 8 |
| 1989 | 47.7 | 9 |
| 1988 | 47.5 | 10 |
| 1987 | 47.5 | 11 |
| 1986 | 47.4 | 11 |