| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2015 | 2 | 136 |
| 2014 | 3 | 144 |
| 2013 | 2 | 151 |
| 2012 | 2 | 152 |
| 2011 | 3 | 153 |
| 2010 | 3 | 149 |
| 2009 | 2 | 149 |
| 2008 | 3 | 146 |
| 2007 | 5 | 125 |
| 2006 | 3 | 135 |
| 2005 | 2 | 135 |
| 2004 | 2 | 129 |
| 2003 | 2 | 122 |
| 2002 | 1 | 138 |
| 2001 | 1 | 130 |
| 2000 | 3 | 107 |
| 1999 | 1 | 136 |
| 1998 | 1 | 124 |
| 1997 | 1 | 123 |
| 1996 | 1 | 118 |
| 1995 | 1 | 101 |
| 1994 | 1 | 103 |
| 1993 | 1 | 105 |
| 1992 | 1 | 98 |
| 1991 | 1 | 95 |
| 1990 | 1 | 91 |
| 1989 | 1 | 89 |
| 1988 | 1 | 96 |
| 1987 | 0 | 99 |
| 1986 | 0 | 109 |