| 时间 | 值 （亿美元） | 世界排名 |
|---|---|---|
| 2013 | 1 | 169 |
| 2012 | 2 | 159 |
| 2011 | 1 | 169 |
| 2010 | 1 | 167 |
| 2009 | 1 | 167 |
| 2008 | 1 | 163 |
| 2007 | 0 | 168 |
| 2006 | 0 | 167 |
| 2005 | 0 | 166 |
| 2004 | 0 | 154 |
| 2003 | 0 | 151 |
| 2002 | 0 | 150 |
| 2001 | 0 | 143 |
| 2000 | 0 | 145 |
| 1999 | 0 | 145 |
| 1998 | 1 | 129 |
| 1997 | 1 | 130 |
| 1996 | 1 | 127 |
| 1995 | 0 | 137 |
| 1994 | 0 | 136 |
| 1993 | 0 | 117 |
| 1992 | 1 | 100 |
| 1991 | 1 | 94 |
| 1990 | 1 | 95 |
| 1989 | 1 | 99 |
| 1988 | 0 | 109 |
| 1987 | 1 | 98 |
| 1986 | 1 | 97 |