| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2010 | 64 | 112 |
| 2009 | 55 | 115 |
| 2008 | 52 | 118 |
| 2007 | 54 | 110 |
| 2006 | 47 | 106 |
| 2005 | 35 | 115 |
| 2004 | 26 | 119 |
| 2003 | 22 | 123 |
| 2002 | 15 | 126 |
| 2001 | 11 | 130 |
| 2000 | 8 | 133 |
| 1999 | 6 | 137 |
| 1998 | 8 | 132 |
| 1997 | 7 | 134 |
| 1996 | 4 | 147 |
| 1995 | 5 | 141 |
| 1994 | 5 | 121 |
| 1993 | 5 | 116 |
| 1992 | 25 | 77 |
| 1991 | 12 | 98 |
| 1990 | 13 | 91 |
| 1989 | 12 | 77 |
| 1988 | 10 | 83 |
| 1987 | 8 | 85 |