| 时间 | 值 （美元） | 世界排名 |
|---|---|---|
| 2016 | 25685 | 8 |
| 2015 | 25390 | 10 |
| 2014 | 24982 | 11 |
| 2013 | 24705 | 12 |
| 2012 | 24461 | 13 |
| 2011 | 24450 | 12 |
| 2010 | 24184 | 14 |
| 2009 | 23477 | 12 |
| 2008 | 23595 | 15 |
| 2007 | 23726 | 15 |
| 2006 | 23029 | 16 |
| 2005 | 22556 | 18 |
| 2004 | 22036 | 17 |
| 2003 | 21523 | 18 |
| 2002 | 21114 | 17 |
| 2001 | 20645 | 19 |
| 2000 | 20550 | 17 |
| 1999 | 19557 | 17 |
| 1998 | 18814 | 17 |
| 1997 | 18223 | 17 |
| 1996 | 17735 | 16 |
| 1995 | 17447 | 16 |
| 1994 | 17353 | 16 |
| 1993 | 17132 | 16 |
| 1992 | 17746 | 14 |
| 1991 | 18129 | 13 |
| 1990 | 18213 | 13 |
| 1989 | 18476 | 9 |
| 1988 | 18401 | 8 |
| 1987 | 17972 | 8 |
| 1986 | 17172 | 10 |