| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2015 | 9 | 116 |
| 2014 | 9 | 124 |
| 2013 | 8 | 131 |
| 2012 | 10 | 120 |
| 2011 | 7 | 127 |
| 2010 | 6 | 125 |
| 2009 | 5 | 125 |
| 2008 | 6 | 121 |
| 2007 | 7 | 117 |
| 2006 | 6 | 112 |
| 2005 | 5 | 110 |
| 2004 | 2 | 131 |
| 2003 | 1 | 131 |
| 2002 | 1 | 134 |
| 2001 | 1 | 119 |
| 2000 | 1 | 128 |
| 1999 | 1 | 124 |
| 1998 | 1 | 122 |
| 1997 | 1 | 116 |
| 1991 | 1 | 98 |
| 1990 | 1 | 93 |
| 1989 | 1 | 95 |
| 1988 | 1 | 98 |
| 1987 | 0 | 102 |
| 1986 | 0 | 100 |