| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2013 | 2 | 153 |
| 2012 | 2 | 161 |
| 2011 | 0 | 175 |
| 2010 | 4 | 133 |
| 2009 | 4 | 134 |
| 2008 | 2 | 151 |
| 2007 | 1 | 158 |
| 2006 | 4 | 122 |
| 2005 | 4 | 116 |
| 2004 | 4 | 113 |
| 2003 | 3 | 108 |
| 2002 | 3 | 110 |
| 2001 | 1 | 123 |
| 2000 | 1 | 126 |
| 1999 | 1 | 138 |
| 1998 | 0 | 142 |
| 1997 | 0 | 143 |
| 1996 | 0 | 141 |
| 1995 | 0 | 135 |
| 1994 | 0 | 132 |
| 1993 | 0 | 125 |
| 1992 | 1 | 105 |
| 1991 | 1 | 96 |
| 1990 | 1 | 96 |
| 1989 | 1 | 92 |
| 1988 | 1 | 89 |
| 1987 | 1 | 91 |
| 1986 | 1 | 86 |