| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2015 | 33 | 77 |
| 2014 | 36 | 78 |
| 2013 | 33 | 82 |
| 2012 | 30 | 83 |
| 2011 | 26 | 87 |
| 2010 | 26 | 82 |
| 2009 | 21 | 91 |
| 2008 | 21 | 94 |
| 2007 | 24 | 83 |
| 2006 | 18 | 89 |
| 2005 | 15 | 91 |
| 2004 | 13 | 91 |
| 2003 | 11 | 91 |
| 2002 | 9 | 95 |
| 2001 | 8 | 97 |
| 2000 | 7 | 101 |
| 1999 | 6 | 109 |
| 1998 | 7 | 109 |
| 1997 | 5 | 116 |
| 1996 | 3 | 130 |
| 1995 | 4 | 120 |
| 1994 | 8 | 79 |
| 1993 | 6 | 94 |
| 1992 | 3 | 103 |
| 1991 | 10 | 70 |
| 1990 | 11 | 66 |
| 1989 | 9 | 61 |
| 1988 | 8 | 63 |
| 1987 | 7 | 69 |