| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 40.1 | 39 |
| 2015 | 40.2 | 39 |
| 2014 | 40.5 | 40 |
| 2013 | 40.7 | 40 |
| 2012 | 40.8 | 40 |
| 2011 | 41 | 41 |
| 2010 | 41.2 | 41 |
| 2009 | 41.4 | 41 |
| 2008 | 41.6 | 39 |
| 2007 | 41.8 | 37 |
| 2006 | 41.9 | 37 |
| 2005 | 42.1 | 39 |
| 2004 | 42.3 | 38 |
| 2003 | 42.5 | 39 |
| 2002 | 42.8 | 40 |
| 2001 | 43 | 40 |
| 2000 | 43.1 | 41 |
| 1999 | 43.4 | 42 |
| 1998 | 43.6 | 41 |
| 1997 | 43.9 | 43 |
| 1996 | 44.1 | 42 |
| 1995 | 44.3 | 40 |
| 1994 | 44.4 | 43 |
| 1993 | 44.6 | 43 |
| 1992 | 44.7 | 44 |
| 1991 | 44.7 | 46 |
| 1990 | 44.8 | 48 |
| 1989 | 44.9 | 48 |
| 1988 | 44.9 | 49 |
| 1987 | 45 | 49 |
| 1986 | 45 | 47 |