| 时间 | 值 （美元） | 世界排名 |
|---|---|---|
| 2015 | 28975 | 31 |
| 2014 | 42996 | 25 |
| 2013 | 48400 | 20 |
| 2012 | 51264 | 15 |
| 2011 | 48269 | 21 |
| 2010 | 38498 | 30 |
| 2009 | 37567 | 30 |
| 2008 | 55572 | 15 |
| 2007 | 45794 | 22 |
| 2006 | 42718 | 20 |
| 2005 | 35490 | 27 |
| 2004 | 26921 | 33 |
| 2003 | 22072 | 35 |
| 2002 | 17789 | 39 |
| 2001 | 16541 | 37 |
| 2000 | 18389 | 36 |
| 1999 | 15391 | 39 |
| 1998 | 14127 | 41 |
| 1997 | 17696 | 32 |
| 1996 | 19301 | 28 |
| 1995 | 16882 | 33 |
| 1991 | 5408 | 54 |
| 1990 | 8777 | 40 |
| 1989 | 11594 | 33 |
| 1988 | 10149 | 34 |
| 1987 | 11512 | 29 |
| 1986 | 9751 | 29 |