| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 100 | 2 |
| 2015 | 100 | 5 |
| 2014 | 100 | 1 |
| 2013 | 100 | 1 |
| 2012 | 100 | 4 |
| 2011 | 100 | 2 |
| 2010 | 100 | 5 |
| 2009 | 100 | 5 |
| 2008 | 100 | 4 |
| 2007 | 100 | 1 |
| 2006 | 100 | 1 |
| 2005 | 100 | 7 |
| 2004 | 100 | 5 |
| 2003 | 100 | 5 |
| 2002 | 100 | 2 |
| 2001 | 100 | 1 |
| 2000 | 100 | 7 |
| 1999 | 100 | 5 |
| 1998 | 100 | 6 |
| 1997 | 100 | 5 |
| 1996 | 100 | 6 |
| 1995 | 100 | 4 |
| 1994 | 100 | 2 |
| 1993 | 100 | 2 |
| 1992 | 99.98 | 6 |
| 1991 | 99.83 | 6 |
| 1990 | 99.52 | 7 |
| 1989 | 99.09 | 7 |
| 1988 | 98.31 | 7 |
| 1987 | 96.86 | 8 |
| 1986 | 94.25 | 10 |