| 时间 | 值 （美元） | 世界排名 |
|---|---|---|
| 2015 | 26599 | 8 |
| 2014 | 26680 | 8 |
| 2013 | 26873 | 8 |
| 2012 | 26214 | 8 |
| 2011 | 25652 | 8 |
| 2010 | 25703 | 9 |
| 2009 | 25105 | 9 |
| 2008 | 25281 | 10 |
| 2007 | 25552 | 11 |
| 2006 | 25345 | 10 |
| 2005 | 25101 | 10 |
| 2004 | 24797 | 9 |
| 2003 | 24485 | 9 |
| 2002 | 24376 | 7 |
| 2001 | 24148 | 7 |
| 2000 | 23755 | 6 |
| 1999 | 23426 | 6 |
| 1998 | 23199 | 6 |
| 1997 | 23400 | 6 |
| 1996 | 23294 | 6 |
| 1995 | 22876 | 6 |
| 1994 | 22404 | 6 |
| 1993 | 21980 | 5 |
| 1992 | 21815 | 6 |
| 1991 | 21418 | 6 |
| 1990 | 21025 | 6 |
| 1989 | 20055 | 6 |
| 1988 | 19209 | 6 |
| 1987 | 18347 | 6 |
| 1986 | 17667 | 6 |