| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 43 | 20 |
| 2015 | 43.1 | 20 |
| 2014 | 43.1 | 22 |
| 2013 | 43.2 | 23 |
| 2012 | 43.2 | 25 |
| 2011 | 43.2 | 26 |
| 2010 | 43.2 | 28 |
| 2009 | 43.3 | 29 |
| 2008 | 43.4 | 31 |
| 2007 | 43.5 | 30 |
| 2006 | 43.5 | 30 |
| 2005 | 43.7 | 30 |
| 2004 | 43.9 | 30 |
| 2003 | 44.1 | 29 |
| 2002 | 44.3 | 28 |
| 2001 | 44.6 | 28 |
| 2000 | 44.8 | 27 |
| 1999 | 45.1 | 27 |
| 1998 | 45.4 | 23 |
| 1997 | 45.7 | 22 |
| 1996 | 45.9 | 20 |
| 1995 | 46 | 21 |
| 1994 | 46.3 | 19 |
| 1993 | 46.5 | 19 |
| 1992 | 46.7 | 17 |
| 1991 | 46.9 | 16 |
| 1990 | 47 | 17 |
| 1989 | 47.1 | 15 |
| 1988 | 47.3 | 11 |
| 1987 | 47.4 | 12 |
| 1986 | 47.4 | 10 |