| 时间 | 值 （美元） | 世界排名 |
|---|---|---|
| 2016 | 28220 | 5 |
| 2015 | 27924 | 7 |
| 2014 | 27607 | 7 |
| 2013 | 27596 | 7 |
| 2012 | 27634 | 6 |
| 2011 | 27597 | 6 |
| 2010 | 27635 | 7 |
| 2009 | 27542 | 6 |
| 2008 | 28674 | 7 |
| 2007 | 28702 | 6 |
| 2006 | 28329 | 6 |
| 2005 | 27608 | 6 |
| 2004 | 26697 | 6 |
| 2003 | 25577 | 6 |
| 2002 | 25309 | 6 |
| 2001 | 25028 | 6 |
| 2000 | 25061 | 5 |
| 1999 | 25048 | 5 |
| 1998 | 25161 | 5 |
| 1997 | 24672 | 5 |
| 1996 | 24066 | 5 |
| 1995 | 23623 | 5 |
| 1994 | 23354 | 5 |
| 1993 | 21970 | 6 |
| 1992 | 22235 | 5 |
| 1991 | 21751 | 5 |
| 1990 | 21459 | 5 |
| 1989 | 21323 | 5 |
| 1988 | 21268 | 5 |
| 1987 | 21676 | 5 |
| 1986 | 22124 | 4 |